Cell membrane penetrating conjugates

ABSTRACT

A cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule wherein the β helical protein length is in the range of from 5 nm to 25 nm, suitably, from 10 nm to 15 nm and width is in the range of from 1 nm to 5 nm, suitably, from 1 nm to 3 nm. Processes for preparing said conjugates and uses thereof are also disclosed.

FIELD OF INVENTION

The present disclosure broadly relates to the field of drug delivery to the cytoplasm of cells and particularly discloses a conjugate comprising a recombinant protein linked to a functional molecule for penetrating cellular membranes, methods of preparing said conjugates and uses thereof.

BACKGROUND OF THE INVENTION

A cell membrane is a semi-permeable membrane which separates the inner environment of a cell from its external environment. Membranes of prokaryotic and eukaryotic cells while differing in some properties and composition both comprise a semi-permeable bilayer structure of phospholipids. The semi-permeable nature of the cell membrane makes it selective for the type of molecules able to penetrate it. Those molecules capable of penetrating cell membranes hold promise for use in cell labelling, cell penetration, cell delivery, drug uptake, gene therapy and many other applications which involve penetration of the cell membrane.

There are certain peptides which can penetrate the cell membrane and translocate to the cytosol, such peptides are termed as cell penetrating peptides (CPPs). CPP conjugates, where the CPP is attached to one or more functional molecules, have been studied as a means to transport various biologically active molecules across the membrane. For example, absorption of insulin was drastically increased (6-8 times) in Caco-2 cells when treated with the CPP conjugate, CPP-insulin (Liang et al., Biochem. Biophys. Res. Commun.; 2005; 335(3): 734-738). Similar results were seen for a conjugate comprising the Tat peptide (ibid.). Another study has reported use of a short amphipathic peptide carrier Pep-1 which could penetrate the membrane and deliver various peptides and proteins in several cell lines (Morris et al., Nature Biotechnol., 2001, 1173-1176).

CPPs have also been used to study the efficient delivery of various anti-cancer drugs as drug-CPP conjugates which could penetrate cell membranes more efficiently than the drug alone because of the properties of the CPP. One such study reported the use of Tat protein conjugated with a CK2 inhibitor (P15) to treat solid tumours (Perea et al., Cancer Res. 2004, 7127-7129).

There are also several molecular transporters which can deliver molecules across cell membranes. Guanidinium-rich molecular transporters (GR-MoTrs) comprising peptide and non-peptide agents have been shown to penetrate cell membrane owing to their number and spatial array of guanidinium groups. GR-MoTrs can enhance delivery of various cargos including small molecules, metals, imaging agents, iron particles, and proteins inside mammalian cells (Wender et al., Adv. Drug Deliv. Rev. 2008, 452-472; Wender et al., Drug Discov. Today Technol. 2012, e49-e55).

US20130137644 discloses a conjugate made up of a cell penetrating peptide, nucleic acid and a hydrophilic polymer which can penetrate cell membranes with increased efficiency. The nucleic acid used in the conjugate is described as preferably being an siRNA, with polyethylene glycol (PEG) as the hydrophilic polymer.

US20040176282 discloses methods and uses of compositions for the cellular delivery of nucleic acids, polypeptides, fluorophores, molecular complexes. The intracellular release of the biologically active molecules after cell penetration is stimulated by light-activated dispersal of the complex. This system helps in repressing the biological functions of the molecules while being a part of the complex, but once inside the cell and upon light activation it can be dispersed and its biological activity can be restored.

One example of a promising and widely used technique involving functional molecules crossing the cell membrane barrier is gene therapy. Gene therapy involves delivering a gene of interest to cells to compensate for abnormal activity of genes or to provide a beneficial protein. Gene therapy has proven beneficial in treating diseases like chronic lymphocytic leukaemia, X-linked SCID, multiple myeloma, haemophilia amongst many others. Many life-threatening diseases have an underlying genetic origin, i.e. the diseases are due to malfunctioning or lack of proper functioning displayed by one or more associated genes. Gene therapy has shown promise for treatment of such disease conditions. However, gene therapy still faces a challenge in terms of delivering the required genes across a cell membrane. To date, two approaches for delivering the genes have been used—viral based and non-viral based.

The viral based approach for gene therapy makes use of attenuated viruses as vectors in which the desired gene is cloned and transferred into the required cells via a process known as transduction. This approach, has the advantage of suitable integration of the delivered gene into the genome of the cells but suffers from other disadvantages, one of them being a tendency to induce cancer in case of inappropriate genome integration. The non-viral based approach includes the use of injecting isolated DNA into the cells and the use of cationic lipids for surrounding a plasmid DNA (lipofection). The non-viral approaches do not require any integration of the gene into the genome and are inefficient in transferring the required genes to other cells in the tissues. Therefore gene therapy, although a promising and an excellent technique for treating a number of life-threatening disorders, suffers from the problem of delivery of genes into the cells.

For the most common inherited disorders, such as cystic fibrosis or muscular dystrophy, effective gene therapy is likely to remain a challenge due to the difficulties in delivering the genetic material into the cell. There is not yet a simple way to deliver genes to a significant proportion of cells in tissues such as the lung epithelium or skeletal muscle (Collins et al., Proc. R. Soc. B. Vol. 282. No. 1821. The Royal Society, 2015). Hence, an effective mechanism of cell delivery is required which can greatly enhance the benefits of gene therapy and expand the avenues for providing promising treatments for many life-threatening diseases.

In addition, and general to the delivery of all functional molecules to the cells, is that most of the mechanisms developed for cellular delivery suffer rely on an endocytosis-dependent mechanism for gaining entry inside the cells. The efficiency of translocation is a major area of concern in endocytosis dependent pathways due to, for example, the possibility of drugs getting trapped in endosomes or degraded in lysosomes. Hence there is a pressing need for devising novel mechanisms for penetrating cell membranes, which can be more reliable and efficacious.

SUMMARY OF INVENTION

These and other features, aspects, and advantages of the present subject matter will be better understood with reference to the following description and appended claims. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

In a first aspect of the present disclosure, there is provided a cell-penetrating conjugate comprising at least one recombinant β helical protein molecule linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm.

In a second aspect of the present disclosure, there is provided a process for transferring a functional molecule into a cell, said process comprising: (a) linking the functional molecule to a recombinant β helical protein to obtain a conjugate; and (b) contacting the cell-penetrating conjugate with at least one cell; wherein contacting the conjugate with the at least one cell transfers the nucleic acid molecule into the cell, and wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm.

In a third aspect, the present disclosure is directed to use of the cell penetrating conjugate of the first aspect of the invention for delivering a functional molecule into cells, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localising signals, nanoparticles and combinations thereof.

In a fourth aspect, the present disclosure is directed to use of the cell penetrating conjugate of the first aspect of the invention for cell penetration.

In a fifth aspect, the present disclosure is directed to use of the cell penetrating conjugate of the first aspect of the invention for cell labelling.

In a sixth aspect of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm.

In a seventh aspect of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell, said process comprising: (i) linking the nucleic acid molecule to at least one recombinant β helical protein via at least one linker to obtain a conjugate; and (ii) contacting the conjugate with at least one cell, wherein contacting the conjugate with the at least one cell transfers the nucleic acid molecule into the cell, and wherein the recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm.

In an eighth aspect, the present disclosure is directed to use of the cell penetrating conjugate of the sixth aspect of the invention as a transfecting agent.

In a ninth aspect, the present disclosure is directed to use of the cell penetrating conjugate of the sixth aspect of the invention for gene therapy.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

The following drawings form a part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.

FIG. 1 shows the CD (circular dichroism) spectra of the isolated AlbG protein, in accordance with the present disclosure.

FIG. 2 shows an agarose gel containing purified plasmids (containing AlbG and EfsQNR genes), in accordance with the present disclosure.

FIG. 3 shows a poly-acrylamide gel containing purified proteins (AlbG and EfsQNR), in accordance with the present disclosure.

FIG. 4 shows MALDI-TOF mass spectral analysis of the EfsQNR and AlbG proteins.

FIG. 5 shows the graphical representation of characterization of labelled proteins (AlbG-NHSC and EfsQNR-NHSC) by UV-visible spectrophotometry, in accordance with an embodiment of the present disclosure.

FIGS. 6A-6D show differential labelling of Hela cells by labelled proteins (conjugates) AlbG-NHSC (FIG. 6C), EfsQNR-NHSC (FIG. 6D) and TtCuA-NHSC (FIG. 6B), relative to a control (FIG. 6A), in accordance with embodiments of the present disclosure.

FIGS. 7A and 7B show labelling of Hela cells by EfsQNR labelled with ATTO-520 (commercially available green fluorescent dye), in accordance with an embodiment of the present disclosure.

FIG. 8 shows labelling of Hela cells by EfsQNR labelled with ATTO-390 (commercially available blue fluorescent dye), in accordance with an embodiment of the present disclosure.

FIGS. 9A and 9B show labelling of microglial cells by EfsQNR labelled with ATTO-520 (commercially available green fluorescent dye), in accordance with an embodiment of the present disclosure (FIG. 9A); and differential labelling of microglial cells by EfsQNR labelled with ATTO-520 (FIG. 9B).

FIG. 10 shows labelling of keratinocyte cells by EfsQNR labelled with ATTO-520 (commercially available green fluorescent dye), in accordance with an embodiment of the present disclosure (Panel A); and differential labelling of keratinocyte cells by EfsQNR labelled with ATTO-520 (Panel B).

FIG. 11 shows labelling of SH-SY5Y cells by EfsQNR labelled with ATTO-520 (commercially available green fluorescent dye), in accordance with an embodiment of the present disclosure.

FIG. 12 shows labelling of mouse ES cells by EfsQNR labelled with ATTO-520 (commercially available green fluorescent dye), in accordance with an embodiment of the present disclosure.

FIG. 13 shows labelling of E. coli cells by EfsQNR labelled with ATTO-520 (commercially available green fluorescent dye), in accordance with an embodiment of the present disclosure.

FIG. 14 shows labelling of yeast (kluveromyces) cells by EfsQNR labelled with ATTO-520 (commercially available green fluorescent dye), in accordance with an embodiment of the present disclosure.

FIGS. 15A-15D show the results of standard FACS sorting of HeLa cells treated with a conjugate labelled with the conjugate EfsQNR-ATTO-647N for 10 mins (FIG. 15B), 1 h (FIG. 15C) and 3 h (FIG. 15D) compared to untreated cells (FIG. 15A).

FIG. 16 shows percentage cellular uptake of a drug as part of a conjugate in accordance with an embodiment of the present disclosure, as compared to unconjugated drug.

FIG. 17 shows percentage viability of cells (Hela and HepG2) after treatment with Cisplatin® a chemotherapy drug as part of a conjugate with the protein EfsQNR (labelled CYDD) in accordance with an embodiment of the present disclosure, as compared to unconjugated drug.

FIG. 18 shows a plasmid vector carrying mcherry gene, in accordance with an embodiment of the present disclosure.

FIG. 19 shows a process for preparing a conjugate, in accordance with an embodiment of the present disclosure.

FIG. 20 shows a representation of transfection using a conjugate, in accordance with an embodiment of the present disclosure.

FIG. 21 shows confocal microscopy images of HeLa cells after transfection with a conjugate in accordance with the present invention; the conjugate comprising the mcherry gene coding for RFP (Red Fluorescent Protein) linked via copper [II] phenanthroline to the EfsQNR protein.

FIG. 22 shows real-time direct penetration of a cell membrane by an EfsQNR-ATTO 520 conjugate in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.

Definitions

For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in the light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

Unless otherwise indicated, the practice of the present invention employs conventional techniques of chemistry, molecular biology, microbiology, recombinant DNA technology, and chemical methods, which are within the capabilities of a person of ordinary skill in the art. Such techniques are also explained in the literature, for example, M. R. Green, J. Sambrook, 2012, Molecular Cloning: A Laboratory Manual, Fourth Edition, Books 1-3, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.; Ausubel, F. M. et al. (1995 and periodic supplements; Current Protocols in Molecular Biology, ch. 9, 13, and 16, John Wiley & Sons, New York, N. Y.); B. Roe, J. Crabtree, and A. Kahn, 1996, DNA Isolation and Sequencing: Essential Techniques, John Wiley & Sons; J. M. Polak and James O'D. McGee, 1990, In Situ Hybridisation: Principles and Practice, Oxford University Press; M. J. Gait (Editor), 1984, Oligonucleotide Synthesis: A Practical Approach, IRL Press; and D. M. J. Lilley and J. E. Dahlberg, 1992, Methods of Enzymology: DNA Structure Part A: Synthesis and Physical Analysis of DNA Methods in Enzymology, Academic Press. Each of these general texts is herein incorporated by reference.

The articles ‘a’, ‘an’ and ‘the’ are used to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article.

As used herein, the term ‘comprising’ means any of the recited elements are necessarily included and other elements may optionally be included as well. ‘Consisting essentially of’ means any recited elements are necessarily included, elements which would materially affect the basic and novel characteristics of the listed elements are excluded, and other elements may optionally be included. ‘Consisting of’ means that all elements other than those listed are excluded. Embodiments defined by each of these terms are within the scope of this invention.

The term ‘including’ is used to mean ‘including but not limited to’. ‘Including’ and ‘including but not limited to’ are used interchangeably.

As used herein, the term ‘cell membrane’ is a biological membrane which is present in both prokaryotic and eukaryotic cells and separates the inner and outer environment of a cell. It acts as a semi-permeable barrier which checks the transport of substances in and out of the cell and is typically formed of a phospholipid bilayer. The membrane acts as a support and helps in maintaining the shape and structure of a cell.

As used herein the term ‘β helical protein’ means a protein forming a β helical secondary structure. β helical proteins are formed from a generally parallel association between adjacent β strands of a peptide chain. A β helical protein can be a right handed β helical or a left handed β helical depending on the direction of coiling of the helix structure.

As used herein the term ‘Pentapeptide-repeat protein (PRP)’ means β helical proteins consisting of a tandemly repeated pentapeptide. In embodiments, the tandemly repeated pentapeptide has the consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅. The PRP family has well over 500 members in the prokaryotic and eukaryotic kingdom.

As used herein the term ‘functional molecule’ is any molecule that has a utility within a cell. Examples of functional molecules suitable for use in the present invention include dyes, drug molecules, proteins, enzymes, antibodies, and nucleic acids.

As used herein the term ‘cell penetrating peptide’ or ‘CPP’ relates to peptides sequences that facilitate cellular intake/uptake of various functional molecules. Cell penetrating peptides generally deliver the functional molecule directly through the cell membrane avoiding the need for endocytosis mediated pathways for cellular entry.

As used herein the term ‘P-cadherin’ refers to a cell to cell adhesion molecule having a homeostatic function in normal tissues. The over expression of this molecule is associated with significant tumour promoting effects in the breast, ovarian, prostate, endometrial, skin, gastric, pancreas and colon neoplasms.

As used herein the term ‘NHS-coumarin’ or ‘NHSC’ refers to a fluorescent dye widely used in cell biology techniques. It is a common name for 7-(diethylamino)coumarin-3-carboxylic acid N-succinimidyl ester having a molecular weight of 358.35 g/mol. NHS-coumarin (NHSC) has an excitation wavelength of 445 nm and an emission wavelength at 482 nm. On observation under fluorescent microscopy, it emits green fluorescence indicating the location and quantification of the molecule conjugated along with this dye.

As used herein the term ‘phosphatidyl choline’ defines a class of phospholipids molecules that incorporate a choline as a headgroup. Phosphatidyl choline may be used as a signalling molecule that facilitates selective binding and attachment with cell membranes.

As used herein the term ‘Hoechst 33342’ refers to a solution of fluorescent dye that is used for both fixed and live cell staining of DNA and nuclei in cellular imaging techniques. Hoechst 33342 is a cell-permeable DNA stain having an excitation wavelength of 460 nm and an emission wavelength of 490 nm and it preferentially binds to adenine(A)-thymine(T) region of DNA.

As used herein the term ‘ATTO 520’, ‘ATTO 390’ and ‘ATTO 647N’ refer respectively to fluorescent dyes developed by the ATTO-Tec GmbH and commercially available from Sigma Aldrich.

As used herein the term ‘Ruthenium metal complex’ refers to the coordination complex of ruthenium metal which is known to possess anti-cancer activities. Octahedral ruthenium (III) and ruthenium (II) complexes display anti-neoplastic activities on many experimental tumours. Ruthenium metal complex is considered as an excellent alternative to circumvent the side-effects of platinum based compounds. A non-limiting example of a ruthenium metal complex that has been demonstrated for use in the present invention is tricarbonyl dichloro ruthenium(II) (ex-Sigma Aldrich).

The term ‘nucleic acid’ as used herein, is a single or double stranded covalently-linked sequence of nucleotides in which the 3′ and 5′ ends on each nucleotide are joined by phosphodiester bonds. The polynucleotide may be made up of deoxyribonucleotide bases or ribonucleotide bases. Nucleic acids may include DNA and RNA, and are typically manufactured synthetically, but may also be isolated from natural sources. Nucleic acids may further include modified DNA or RNA, for example DNA or RNA that has been methylated or that has been subject to chemical modification, for example 5′-capping with 7-methylguanosine, 3′-processing such as cleavage and polyadenylation, and splicing, or labelling with fluorophores or other compounds. Nucleic acids may also include synthetic nucleic acids (XNA), such as hexitol nucleic acid (HNA), cyclohexene nucleic acid (CeNA), threose nucleic acid (TNA), glycerol nucleic acid (GNA), locked nucleic acid (LNA) and peptide nucleic acid (PNA). Hence, where the terms ‘DNA’ and ‘RNA’ are used herein it should be understood that these terms are not limited to only include naturally occurring nucleotides. Sizes of nucleic acids, also referred to herein as ‘polynucleotides’ are typically expressed as the number of base pairs (bp) for double stranded polynucleotides, or in the case of single stranded polynucleotides as the number of nucleotides (nt). One thousand bp or nt equal a kilobase (kb). Polynucleotides of less than around 100 nucleotides in length are typically called ‘oligonucleotides’.

As used herein, the terms ‘3′’ (‘3 prime’) and ‘5′’ (‘5 prime’) take their usual meanings in the art, i.e. to distinguish the ends of polynucleotides. A polynucleotide has a 5′ and a 3′ end and polynucleotide sequences are conventionally written in a 5′ to 3′ direction.

The term ‘amino acid’ in the context of the present invention is used in its broadest sense and is meant to include naturally occurring L a-amino acids or residues. The commonly used one and three letter abbreviations for naturally occurring amino acids are used herein: A=Ala; C=Cys; D=Asp; E=Glu; F=Phe; G=Gly; H=His; I=Ile; K=Lys; L=Leu; M=Met; N=Asn; P=Pro; Q=Gln; R=Arg; S=Ser; T=Thr; V=Val; W=Trp; and Y=Tyr (Lehninger, A. L., (1975) Biochemistry, 2d ed., pp. 71-92, Worth Publishers, New York). The general term ‘amino acid’ further includes D-amino acids, retro-inverso amino acids as well as chemically modified amino acids such as amino acid analogues, naturally occurring amino acids that are not usually incorporated into proteins such as norleucine, and chemically synthesised compounds having properties known in the art to be characteristic of an amino acid, such as β-amino acids. For example, analogues or mimetics of phenylalanine or proline, which allow the same conformational restriction of the peptide compounds as do natural Phe or Pro, are included within the definition of amino acid. Such analogues and mimetics are referred to herein as ‘functional equivalents’ of the respective amino acid. Other examples of amino acids are listed by Roberts and Vellaccio, The Peptides: Analysis, Synthesis, Biology, Gross and Meiehofer, eds., Vol. 5 p. 341, Academic Press, Inc., N.Y. 1983, which is incorporated herein by reference.

A ‘polypeptide’ is a polymer of amino acid residues joined by peptide bonds, whether produced naturally or in vitro by synthetic means. Polypeptides of less than around 12 amino acid residues in length are typically referred to as ‘peptides’ and those between about 12 and about 30 amino acid residues in length may be referred to as ‘oligopeptides’. The term ‘polypeptide’ as used herein denotes the product of a naturally occurring polypeptide, precursor form or proprotein. Polypeptides can also undergo maturation or post-translational modification processes that may include, but are not limited to: glycosylation, proteolytic cleavage, lipidization, signal peptide cleavage, propeptide cleavage, phosphorylation, and such like. The term ‘protein’ is used herein to refer to a macromolecule comprising one or more polypeptide chains.

The term ‘isolated’, when applied to a polynucleotide or protein sequence, denotes that the sequence has been removed from its natural organism of origin and is, thus, free of extraneous or unwanted coding or regulatory sequences. The isolated sequence is suitable for use in assembly of compositions and nanostructures of the present invention. Such isolated sequences may include cDNAs and RNAs.

According to the present invention, homology to the nucleic acid or protein sequences described herein is not limited simply to 100% sequence identity. Any closely related nucleic acid or protein sequences to those specified herein that demonstrate functional and/or biochemical equivalence are considered within the scope of the present invention as defined by the claims.

The term ‘signal sequence’ in the context of the present invention means nuclear localizing sequence or recognition sequences for different cell organelles or nucleic acid binding domains such as zinc finger binding proteins.

As used herein the term ‘carrier’ means substances that serve as mechanisms to improve the delivery and the effectiveness of the drug.

As used herein the term ‘diluent’ (also referred to as filler, dilutant, or thinner) means a diluting agent.

As used herein the term ‘excipient’ refers to an inactive substance that serves as a vehicle or medium for a drug or other active substance. Excipients include colouring agents, humectants, preservatives, emollients and combinations thereof.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.

Sequences SEQ ID NO: 1 depicts amino acid sequence of AlbG protein. MPAKTLESKDYCGESFVSEDRSGQSLESIRFEDCTFRQCNFTEAELNRCKF RECEFVDCNLSLISIPQTSFMEVRFVDCKMLGVNWTSAQWPSVKMEGALSF ERCILNDSLFYGLYLAGVKMVECRIHDANFTEADCEDADFTQSDLKGSTFH NTKLTGASFIDAVNYHIDIFHNDIKRARFSLPEAASLLNSLDIELSD SEQ ID NO: 2 depicts amino acid sequence of EfsQNR protein. GSHMKITYPLPPNLPEQLPLLTNCQLEDEAILENHLYQQIDLPNQEVRNLV FRDAVFDHLSLANGQFASFDCSNVRFEACDFSNVEWLSGSFHRVTFLRCNL TGTNFADSYLKDCLFEDCKADYASFRFANFNLVHFNQTRLVESEFFEVTWK KLLLEACDLTESNWLNTSLKGLDFSQNTFERLTFSPNYLSGLKVTPEQAIY LASALGLVIT SEQ ID NO: 3 depicts amino acid sequence of anti- freeze protein from Tenebrio molitor. QCTGGADCTSCTGACTGCGNCPNAVTCTNSQHCVKANTCTGSTDCNTAQTC TNSKDCFEANTCTDSTNCYKATACTNSSGCPGH SEQ ID NO: 4 depicts amino acid sequence of anti- freeze protein from Rhagium inquisitor. GYSCRAVGVDGRAVTDIQGTCHAKATGAGAMASGTSEPGSTSTATATGRGA TARSTSTGRGTATTTATGTASATSNAIGQGTATTTATGSAGGRATGSATTS SSASQPTQTQTITGPGFQTAKSFARNTATTTVTASHHHHHH SEQ ID NO: 5 depicts amino acid sequence of anti- freeze protein from Spruce Budworm (Choristoneura fumiferana). DGSCTNTNSQLSANSKCEKSTLTNCYVDKSEVYGTTCTGSRFDGVTITTST STGSRISGPGCKISTCIITGGVPAPSAACKISGCTFSAN SEQ ID NO: 6 depicts amino acid sequence of QNRB1 protein. GSHMALALVGEKIDRNRFTGEKIENSTFFNCDFSGADLSGTEFIGCQFYDR ESQKGCNFSRAMLKDAIFKSCDLSMADFRNSSALGIEIRHCRAQGADFRGA SFMNMITTRTWFCSAYITNTNLSYANFSKVVLEKCELWENRWIGAQVLGAT FSGSDLSGGEFSTFDWRAANFTHCDLTNSELGDLDIRGVDLQGVKLDNYQA SLLMERLGIAVIG SEQ ID NO: 7 depicts amino acid sequence of UDP-N- acetylglucosamine acyltransferase protein. MIDKSAFVHPTAIVEEGASIGANAHIGPFCIVGPHVEIGEGTVLKSHVVVN GHTKIGRDNEIYQFASIGEVNQDLKYAGEPTRVEIGDRNRIRESVTIHRGT VQGGGLTKVGSDNLLMINAHIAHDCTVGNRCILANNATLAGHVSVDDFAII GGMTAVHQFCIIGAHVMVGGCSGVAQDVPPYVIAQGNHATPFGVNIEGLKR RGFSREAITAIRNAYKLIYRSGKTLDEVKPEIAELAETYPEVKAFTDFFAR STRGLIR SEQ ID NO: 8 depicts amino acid sequence of NP275 protein from Nostoc punctiforme. MGSSHHHHHHSSGLVPRGSHMDVEKLRQLYAAGERDFSIVDLRGAVLENIN LSGAILHGAMLDEANLQQANLSRADLSGATLNGADLRGANLSKADLSDAIL DNAILEGAILDEAVLNQANLKAANLEQAILSHANIREADLSEANLEAADLS GADLAIADLHQANLHQAALERANLTGANLEDANLEGTILEGGNNNLAT SEQ ID NO: 9 depicts amino acid sequence of pectate lyase C. ATDTGGYAATAGGNVTGAVSKTATSMQDIVNIIDAARLDANGKKVKGGAYP LVITYTGNEDSLINAAAANICGQWSKDPRGVEIKEFTKGITIIGANGSSAN FGIWIKKSSDVVVQNMRIGYLPGGAKDGDMIRVDDSPNVWVDHNELFAANH ECDGTPDNDTTFESAVDIKGASNTVTVSYNYIHGVKKVGLDGSSSSDTGRN ITYHHNYYNDVNARLPLQRGGLVHAYNNLYTNITGSGLNVRQNGQALIENN WFEKAINPVTSRYDGKNFGTWVLKGNNITKPADFSTYSITWTADTKPYVNA DSWTSTGTFPTVAYNYSPVSAQCVKDKLPGYAGVGKNLATLTSTACK SEQ ID NO: 10 depicts amino acid sequence of pectate lyase from Caldicellulosiruptor bescii VGTNTGGVLVITDTIIVKSGQTYDGKGIKIIAQGMGDGSQSENQKPIFKLE KGANLKNVIIGAPGCDGIHCYGDNVVENVVWEDVGEDALTVKSEGVVEVIG GSAKEAADKVFQLNAPCTFKVKNFTATNIGKLVRQNGNTTFKVVIYLEDVT LNNVKSCVAKSDSPVSELWYHNLNVNNCKTLFEFPSQSQIHQY SEQ ID NO: 11 depicts amino acid sequence of carbonic anhydrase from Methanosarcina thermophila. QEITVDEFSNIRENPVTPWNPEPSAPVIDPTAYIDPQASVIGEVTIGANVM VSPMASIRSDEGMPIFVGDRSNVQDGVVLHALETINEEGEPIEDNIVEVDG KEYAVYIGNNVSLAHQSQVHGPAAVGDDTFIGMQAFVFKSKVGNNCVLEPR SAAIGVTIPDGRYIPAGMVVTSQAEADKLPEVTDDYAYSHTNEAVVYVNVH LAEGYKETS SEQ ID NO: 12 depicts amino acid sequence of Pectin lyase A protein from Aspergillus niger. VGVSGSAEGFAKGVTGGGSATPVYPDTIDELVSYLGDDEARVIVLTKTFDF TDSEGTTTGTGCAPWGTASACQVAIDQDDWCENYEPDAPSVSVEYYNAGTL GITVTSNKSLIGEGSSGAIKGKGLRIVSGAENIIIQNIAVTDINPKYVWGG DDAITLDCDLVWIDHVTTARIGRQHYVLGTSADNRVSLTNNYIDGVSDYSA TCDGYHYWAIYLDGDADLVTMKGNYIYHTSGRSPKVQDNTLLHAVNNYWYD ISGHAFEIGEGGYVLAEGNVFQNVDTVLETYEGEAFTVPSSTAGEVCSTYL GRDCVINGFGSSGTFSEDSTSFLSDFEGKNIASASAYTSVASRVVANAGQG NL SEQ ID NO: 13 depicts amino acid sequence of TtCuA protein. AYTLATHTAGVIPAGKLERVDPTTVRQEGPWADPAQAVVQTGPNQYTVYVL AFAFGYQPNPIEVPQGAEIVFKITSPDVIHGFHVEGTNINVEVLPGEVSTV RYTFKRPGEYRIICNQYCGLGHQNMFGTIVVKE SEQ ID NO: 14 depicts a signal sequence for target- ing the nucleus of the cell. PAAKRVKCD SEQ ID NO: 15 depicts a signal sequence for target- ing the endoplasmic reticulum of the cell. YPYDVPDYAKDEL SEQ ID NO: 16 depicts a signal sequence for target- ing the mitochondria of the cell. MLSLRQSIRFFKPATRTLCSSRYLL SEQ ID NO: 17 depicts a signal sequence for target- ing the P-cadherin-over expressing breast cancer cells. LSTAADMQGVVTDGMASGLDKDYLKPDD SEQ ID NO: 18 depicts a consensus sequence in a pentapeptide-repeat protein. (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅ SEQ ID NO: 19 depicts a nucleic acid sequence of AlbG gene. ATGCCGGCGAAAACCCTGGAAAGCAAAGATTATTGCGGCGAAAGCTTTGTG AGCGAAGATCGCAGCGGCCAGAGCCTGGAAAGCATTCGCTTTGAAGATTGC ACCTTTCGCCAGTGCAACTTTACCGAAGCGGAACTGAACCGCTGCAAATTT CGCGAATGCGAATTTGTGGATTGCAACCTGAGCCTGATTAGCATTCCGCAG ACCAGCTTTATGGAAGTGCGCTTTGTGGATTGCAAAATGCTGGGCGTGAAC TGGACCAGCGCGCAGGCGGGCGCGCTGAGCTTTGAACGCTGCATTCTGAAC GATAGCCTGTTTTATGGCCTGTATCTGGCGGGCGTGAAAATGGTGGAATGC CGCATTCATGATGCGAACTTTACCGAAGCGGATTGCGAAGATGCGGATTTT ACCCAGAGCGATCTGAAAGGCAGCACCTTTCATAACACCAAACTGACCGGC GCGAGCTTTATTGATGCGGTGAACTATCATATTGATATTTTTCATAACGAT ATTAAACGCGCGCGCTTTAGCCTGCCGGAAGCGGCGAGCCTGCTGAACAGC CTGGATATTGAACTGAGCGAT SEQ ID NO: 20 depicts a nucleic acid sequence of EfsQNR gene. GGCAGCCATATGAAAATTACCTATCCGCTGCCGCCGAACCTGCCGGAACAG CTGCCGCTGCTGACCAACTGCCAGCTGGAAGATGAAGCGATTCTGGAAAAC CATCTGTATCAGCAGATTGATCTGCCGAACCAGGAAGTGCGCAACCTGGTG TTTCGCGATGCGGTGTTTGATCATCTGAGCCTGGCGAACGGCCAGTTTGCG AGCTTTGATTGCAGCAACGTGCGCTTTGAAGCGTGCGATTTTAGCAACGTG GAATGGCTGAGCGGCAGCTTTCATCGCGTGACCTTTCTGCGCTGCAACCTG ACCGGCACCAACTTTGCGGATAGCTATCTGAAAGATTGCCTGTTTGAAGAT TGCAAAGCGGATTATGCGAGCTTTCGCTTTGCGAACTTTAACCTGGTGCAT TTTAACCAGACCCGCCTGGTGGAAAGCGAATTTTTTGAAGTGACCTGGAAA AAACTGCTGCTGGAAGCGTGCGATCTGACCGAAAGCAACTGGCTGAACACC AGCCTGAAAGGCCTGGATTTTAGCCAGAACACCTTTGAACGCCTGACCTTT AGCCCGAACTATCTGAGCGGCCTGAAAGTGACCCCGGAACAGGCGATTTAT CTGGCGAGCGCGCTGGGCCTGGTGATTACC SEQ ID NO: 21 depicts a nucleic acid sequence of TtCuA gene GCGTATACCCTGGCGACCCATACCGCGGGCGTGATTCCGGCGGGCAAACTG GAACGCGTGGATCCGACCACCGTGCGCCAGGAAGGCCCGTGGGCGGATCCG GCGCAGGCGGTGGTGCAGACCGGCCCGAACCAGTATACCGTGTATGTGCTG GCGTTTGCGTTTGGCTATCAGCCGAACCCGATTGAAGTGCCGCAGGGCGCG GAAATTGTGTTTAAAATTACCAGCCCGGATGTGATTCATGGCTTTCATGTG GAAGGCACCAACATTAACGTGGAAGTGCTGCCGGGCGAAGTGAGCACCGTG CGCTATACCTTTAAACGCCCGGGCGAATATCGCATTATTTGCAACCAGTAT TGCGGCCTGGGCCATCAGAACATGTTTGGCACCATTGTGGTGAAAGAA SEQ ID NO: 22 depicts a signal sequence for target- ing to actin in the cell. GDVQKKRWLFETKPLD SEQ ID NO: 23 depicts a signal sequence for target- ing to tubulin in the cells. VQSKCGSKDNIKHVPGGG SEQ ID NO. 24: depicts an amino acid sequence of a zinc finger protein MERPYACPVESCDRRFSDSSNLTRHIRIHTGQKPFQCRICMRNFSRSDHLT THIRTHTGEKPFACDICGRKFARSDERKRHTKIHLRQKD SEQ ID NO. 25: depicts a nucleic acid sequence of mcherry gene. GTGAGCAAGGGCGAGGAGGATAACATGGCCATCATCAAGGAGTTCATGCGC TTCAAGGTGCACATGGAGGGCTCCGTGAACGGCCACGAGTTCGAGATCGAG GGCGAGGGCGAGGGCCGCCCCTACGAGGGCACCCAGACCGCCAAGCTGAAG GTGACCAAGGGTGGCCCCCTGCCCTTCGCCTGGGACATCCTGTCCCCTCAG TTCATGTACGGCTCCAAGGCCTACGTGAAGCACCCCGCCGACATCCCCGAC TACTTGAAGCTGTCCTTCCCCGAGGGCTTCAAGTGGGAGCGCGTGATGAAC TTCGAGGACGGCGGCGTGGTGACCGTGACCCAGGACTCCTCCCTCCAGGAC GGCGAGTTCATCTACAAGGTGAAGCTGCGCGGCACCAACTTCCCCTCCGAC GGCCCCGTAATGCAGAAGAAGACCATGGGCTGGGAGGCCTCCTCCGAGCGG ATGTACCCCGAGGACGGCGCCCTGAAGGGCGAGATCAAGCAGAGGCTGAAG CTGAAGGACGGCGGCCACTACGACGCTGAGGTCAAGACCACCTACAAGGCC AAGAAGCCCGTGCAGCTGCCCGGCGCCTACAACGTCAACATCAAGTTGGAC ATCACCTCCCACAACGAGGACTACACCATCGTGGAACAGTACGAACGCGCC GAGGGCCGCCACTCCACCGGCGGCATGGACGAGCTGTACAAGTAGTAATCT AGAGGGCCCTATTCTATAGTGTCACC. SEQ ID NO. 26: depicts a nucleic acid sequence of a primer for PCR amplification of the AlbG gene. ATCCCGCTCATATGCCGGCCAAGACCCTTG SEQ ID NO. 27: depicts a nucleic acid sequence of a primer for PCR amplification of the AlbG gene. ATCCCGCTCTCGAGTCAATCGGACAGCTCGATATC SEQ ID NO. 28: depicts a nucleic acid sequence of a primer for PCR amplification of the EfsQNR gene. ATCCCGCTCATATGAAAATAACTTATCCCTTGCCA SEQ ID NO. 29: depicts a nucleic acid sequence of a primer for PCR amplification of the EfsQNR gene. ATCCCGCTCTCGAGTTAGGTAATCACCAAACCAAGT

The present invention also provides for conjugates comprising a recombinant protein and a functional molecule for penetrating cellular membranes, and uses thereof that have substantially similar sequence identity or homology to that of SEQ ID NOs: 1 to 12. The term ‘substantially similar sequence identity’ is used herein to denote a level of sequence similarity of from about 50%, 60%, 70%, 80%, 90%, 95% to about 99% identity. Percent sequence identity can be determined using conventional methods, for example those described in Henikoff and Henikoff Proc. Natl. Acad. Sci. USA 1992; 89:10915, and Altschul et al. Nucleic Acids Res. 1997; 25:3389-3402 for nucleic acids; and for proteins via comparison after alignment using systems such as BLAST®.

Cell Penetrating Conjugate with Functional Molecules

Identifying novel drugs to cure or prevent life threatening diseases remains a highly active area of research. Most of such drugs tend to have targets inside the cells and to reach the target they would have to cross the semi permeable membrane which is not straightforward or efficient in many cases. Therefore, developing novel mechanisms to penetrate the cell membrane remains desirable. On the other hand, scientific investigations and studies aiming to unravel various cellular mechanisms are also seeking to find novel methods of penetrating cell membranes which can help in the labelling of the cell and its various organelles. Also, it would be highly useful in delivering the required materials inside cells for scientific experiments. Most of the cell penetrating molecules described in recent reports involve the endocytosis mechanism of cell entry.

To circumvent the disadvantages of the intake of molecules through endocytosis, for example the entrapment and degradation of drugs in different types of endosomal compartments which eventually fuse with degradative compartment of cells such as lysosomes, a cell membrane penetrating conjugate is disclosed herein which can penetrate the cell membrane to gain access to the inside the cells and can also be used to deliver various cargos including dyes, drugs, proteins, enzymes, antibodies, and nucleic acids inside the cells.

The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally-equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein.

The present invention discloses a conjugate capable of penetrating a cell membrane. The conjugate comprises a recombinant β helical protein, or a recombinant β helical protein portion, linked to a functional molecule wherein the protein has a longest dimension, defined as its length, in the range of 5 nm-25 nm and a width or diameter, defined as the dimension of the protein structure substantially perpendicular to its length, in the range of 1 nm-5 nm. The dimension of the protein in defined as measured in the solid state (characterized by x-ray crystallography or atomic force microscopy) or in solution state (dynamic light scattering measurements).

In embodiments of the present invention, the protein structure of the conjugate may have a longest dimension or length greater than 5 nm, 7.5 nm, 10 nm, 11 nm, 12 nm, 13 nm or 14 nm. In embodiments, the protein structure of the conjugate may have a longest dimension or length less than 25 nm, 20 nm, 17.5 nm, 15 nm, 14 nm, 13 nm, 12 nm or 11 nm. Suitably the length is in the range of from 5 nm to 25 nm, more suitably from 10 nm to 15 nm, even more suitably from 11 nm to 14 nm or 12 nm to 13 nm. In embodiments, the protein structure of the conjugate may have a width or diameter, in a dimension substantially perpendicular to its length, of at least 1 nm, 1.1 nm, 1.2 nm, 1.3 nm, 1.4 nm, 1.5 nm, 1.6 nm, 1.7 nm, 1.8 nm, 1.9 nm or 2.0 nm. In embodiments, the protein structure of the conjugate may have a longest dimension or length less than 5.0mm, 4.5 nm, 4.0 nm, 3.5 nm, 3.0 nm, 2.9 nm, 2.8 nm, 2.7 nm, 2.6 nm, 2.5 nm, 2.4 nm, 2.3 nm, 2.2 nm, 2.1 nm or 2.0 nm. Suitably the width is in the range of from 1 nm to 5 nm, more suitably from 1 nm to 3 nm, even more suitably from 1.5 nm to 2.5 nm.

A surrogate for or an alternative definition for the physical size of the protein portion of the conjugate of the present invention is the combination of its β-helical structure along with its molecular weight. The definition of the size of the protein based on its physical dimensions or on its molecular weight may be used interchangeably. In embodiments of the present invention, the molecular weight of the protein portion may be at least 30 kDa. Suitably, the molecular weight of the protein portion may be at least 35 kDa, 40 kDa, 45 kDa or 50 kDa. In embodiments of the present invention, the molecular weight of the protein portion may be at most 100 kDa. Suitably, the molecular weight of the protein portion may be at most 90 kDa, 80 kDa, 70 kDa, 60 kDa, 55 kDa or 50 kDa. Suitably the molecular weight range of the protein portion of the conjugate of the present invention is in the range of 30-100 kDa, more suitably, 40-60 kDa, even more suitably 48-55 kDa.

Without wishing to be bound by theory, it is envisaged that the beneficial properties in cell penetration demonstrated by the conjugates of the present invention is due to the physical size of the protein portion, as defined by the dimensions or molecular weight outlined above. A further feature of the proteins is the rigidity that derives largely from the uncommon β-helical secondary structure. Suitably the protein may be more rigid than the membrane to be penetrated. Typical cell membranes have a rigidity of 0.005 to 0.02 N/m² (as measured by Atomic Force Mircroscopy; Hayashi, “Tensile Properties and Local Stiffness of Cells”; Mechanics of Biological Tissue, pp 137-152) depending on cell type. Suitably the proteins of the present invention have a rigidity, or high stiffness parameter (K) typical of a β-helix of 0.7 to 12 N/m² (Keten et al., Cell Mol. Bioeng. 2009; 2; 66-74, which is incorporated herein by reference).

A further feature thought to be influential in the efficiency of cell penetration of the conjugates of the present invention is the charge profile and arrangement of the amino acids in the β-helical structure of the protein. Specifically, the presence of charged lysine, arginine asparagine, aspartic acid and/or glutamic acid ‘ladders’ in the β-helical protein structure facilitates penetration of the cell membrane, and the total negative charge of the protein sequence.

The term ‘ladder’ in respect of amino acid residues in β-helical protein structures is defined as a presence of alternatively arranged positively (lysine, arginine and/or asparagine) and negatively charged residues (aspartic acid and/or glutamic acid) along the length of the surface of the protein.

Without wishing to be bound by theory, the presence of charged ‘ladder’ structures in the β-helical structure of the protein according to the present invention could be facilitating the interaction of the protein with the lipid molecules of the cell membrane (e.g. in forming hydrogen bond with the hydroxyl groups of the lipid molecules) and/or first attachment of the protein onto the negatively charged cell membrane.

The total negative charge of the protein according to the present invention due to the negatively charged residues could be facilitating the repulsion leading to angular motion of the protein to make it stand straight on the membrane and puncture the membrane.

In embodiments of the present invention, the protein of the conjugate comprises ladders of alternately arranged surface exposed positively and negatively charged amino acid residues. In embodiments, the protein comprises at least one of an arginine ladder (10-30 Arg residues), a lysine ladder (10-30 Lys residues), an asparagine ladder (10-40 Asn residues), aspartic acid (10-40 Asp residues) and glutamic acid (10-40 Glu residues).

In embodiments of the present invention, the total formal charge of the protein may be zero, or it may be non-zero. Suitably the total formal charge is non-zero, more suitably the total formal charge is below zero (negative). In embodiments the total formal charge of the protein is below (i.e. more negative than) −10. Suitably, the total formal charge of the protein is below −20, −25, −30, −35, −40, −45 or −50. More suitably the total form charge is below −20. In embodiments the total formal charge of the protein is above (i.e. less negative than) −80. Suitably, the total formal charge of the protein is above −70, −65, −60, −55, −50, −45, −40, −35, or −30. More suitably, the total formal charge is above -60. In embodiments, the total formal charge of the protein is in the range of from −10 to −80, more suitably from −20 to −60.

The efficiency of cell penetration and the mechanism of cell penetration may be modulated by optimizing the total formal charge of the conjugates by increasing the number of positively charged residues (e.g. arginine) along the surface of the protein and the sequences can be mutated at the N terminal with the signalling sequences (SEQ ID NOs: 14, 15, 16 or 17 and/or phosphatidyl choline) for attaining specificity of cellular organelles or specificity of particular cancer cells.

In an embodiment, the protein of the conjugate of the present invention suitable for direct cell penetration (i.e. non-endocytotic) may have one or more of the following structural parameters:

-   -   Beta helical structure with stiffness parameter K (beta helix)         0.2 to 12 N/m²;     -   Length between 5 nm to 25 nm;     -   Diameter between 1 nm to 5 nm;     -   Molecular weight between 25 KDa to 100 KDa;     -   Alternatively arranged ladders of surface exposed positive and         negative charge residues on the surface of the protein along the         length: an arginine ladder (10-30 Arg residues), a lysine ladder         (10-30 Lys residues), an asparagine ladder (10-40 Asn residues),         aspartic acid (10-40 Asp residues) and glutamic acid (10-40 Glu         residues);     -   Total formal charge (−20 to −60).

In embodiments of the present invention, the linker between the β-helical protein and the functional molecule may be formed by a direct link between the β-helical protein and the functional molecule, for example via an amide (or peptidic), or ester covalent linkage, or via metal coordination; or the linker may take the form of a linker molecule. Suitably the link is by covalent or non-covalent bonds or interactions. When the linker is a linker molecule the linker molecule may take any suitable form that reversibly connects the β-helical protein and the functional molecule. In some embodiments, the linker molecule may be selected from the group consisting of a peptide or protein, PEG (polyethylene glycol) linker, organic molecule, metal conjugate, drug-metal conjugate, nucleic acid binding domains, and nucleic acid intercalating molecule.

In an embodiment, the present invention discloses a conjugate having a recombinant β helical protein of length in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, wherein the β helical protein has a specific sequence linked to a functional molecule. Suitably the specific sequence is a penta-peptide repeat. In an embodiment, the consensus sequence of the recombinant β helical protein linked to a functional molecule is (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅. Examples of pent-peptide repeat proteins are SEQ ID Nos: 1, 2, 6 and 8.

In embodiments of the present disclosure, the recombinant β helical protein is selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, and SEQ ID NO: 12.

In embodiments of the present invention, the functional molecule can be any organic molecule (anticancer drugs, antibiotics, NSAIDS, pain relieving drugs or any other drug molecule, fluorescent dyes, insecticides, pesticides etc.), drug-metal complex, metal, antibody, protein, polysaccharide, nucleic acids, peptides, nuclear localising signal, quantum dots and nanoparticles.

The conjugate can be used to transfer a functional molecule inside the cells facilitated by the ability of the conjugate to penetrate the cell membrane. With appropriate localising signals associated with or integrated with the conjugate or the functional molecule or both, the conjugate of the present invention can be used to target the functional molecule to a specific part of the interior of the cell, for example, the organelles present inside the cells.

In an embodiment, the present invention also discloses a process for transferring a functional molecule inside the cells using the cell penetrating conjugate of the present invention. The process disclosed can further be used for cell labelling, cell penetration, and targeting of any functional molecule to cell organelles.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the β helical protein is a pentapeptide-repeat protein.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the β helical protein is AlbG having a sequence as set forth in SEQ ID NO: 1.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the β helical protein is EfsQNR having a sequence as set forth in SEQ ID NO: 2.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 3.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 4.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 5.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is QNRB1 having a sequence as set forth in SEQ ID NO: 6.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is UDP N-acetylglucosamine acyltransferase having a sequence as set forth in SEQ ID NO: 7.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is NP275 having a sequence as set forth in SEQ ID NO: 8.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is pectate lyase C having a sequence as set forth in SEQ ID NO: 9.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is a pectate lyase having a sequence as set forth in SEQ ID NO: 10.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is carbonic anhydrase having a sequence as set forth in SEQ ID NO: 11.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is Pectin Lyase A having a sequence as set forth in SEQ ID NO: 12.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a dye.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a drug.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a metal.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a drug-metal complex.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a protein.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is an enzyme.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is an antibody.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a nucleic acid.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a polysaccharide.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a nuclear localising signal.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is a nanoparticle.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is linked to the recombinant β helical protein by covalent bonds, non-covalent bonds, and combinations thereof.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is linked to the recombinant β helical protein by covalent bonds.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the functional molecule is linked to the recombinant β helical protein by non-covalent bonds.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the complex further comprises a signal sequence.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the conjugate further comprises a phospholipid molecule.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the conjugate further comprises a signal sequence selected from the group consisting of SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, and SEQ ID NO: 17.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the conjugate further comprises a phosphatidyl choline molecule.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 14.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 15.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 16.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule as described herein, wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 17.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to nucleus of the cell, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 14.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to nucleus of the cell as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 14.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to nucleus of the cell as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to endoplasmic reticulum of the cell, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 15.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to endoplasmic reticulum of the cell as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 15.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to endoplasmic reticulum of the cell as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to mitochondria of the cell, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 16.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to mitochondria of the cell as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof , and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 16.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to mitochondria of the cell as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to P-cadherin overexpressing breast cancer cells, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 17.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to P-cadherin overexpressing breast cancer cells as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the conjugate further comprises a signal sequence as set forth in SEQ ID NO: 17.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to P-cadherin overexpressing breast cancer cells as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to membrane of the cell, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the conjugate further comprises a phosphatidyl choline molecule.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to membrane of the cell as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the conjugate further comprises a phosphatidyl choline molecule.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule for transferring the functional molecule to membrane of the cell as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell, said process comprising: (a) linking the functional molecule to a recombinant β helical protein to obtain a conjugate; (b) contacting the conjugate with at least one cell wherein contacting the conjugate transfers the functional molecule into the cell, and wherein length of the β helical protein is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm. In an embodiment, the process further comprises after step (c), step (d) detecting the transfer of the conjugate inside the cell.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is a pentapeptide-repeat protein.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is AlbG having a sequence as set forth in SEQ ID NO: 1.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is EfsQNR having a sequence as set forth in SEQ ID NO: 2.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 3.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 4.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 5.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is QNRB1 having a sequence as set forth in SEQ ID NO: 6.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is UDP N acetylglucosamine acyltransferase having a sequence as set forth in SEQ ID NO: 7.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is NP275 having a sequence is as set forth in SEQ ID NO: 8.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is pectate lyase C having a sequence as set forth in SEQ ID NO: 9.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is a pectate lyase having a sequence as set forth in SEQ ID NO: 10.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is carbonic anhydrase having a sequence as set forth in SEQ ID NO: 11.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein having a sequence is as set forth in SEQ ID NO: 12.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a dye.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a drug.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a metal.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a drug-metal complex.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a protein.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is an enzyme.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is an antibody.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a nucleic acid.

In an embodiment of the present disclosure, there is provided process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a polysaccharide.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a nuclear localising signal.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is a nanoparticle.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the functional molecule is linked to the recombinant β helical protein by covalent bonds, non-covalent bonds, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the cell is selected from the group consisting of eukaryotic cells, prokaryotic cells, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the cell is a prokaryotic cell.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the cell is a eukaryotic cell.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is represented by a sequence as set forth in SEQ ID NO: 1, and the functional molecule is NHS-coumarin dye.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is represented by a sequence as set forth in SEQ ID NO: 2, and the functional molecule is NHS-coumarin dye.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the β helical protein is represented by a sequence as set forth in SEQ ID NO: 2, and the functional molecule is ruthenium metal complex.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the process is used for cell-labelling.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule into a cell as described herein, wherein the process is used for delivering the functional molecules into the cell.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to an organelle of a cell, said process comprising: (a) linking the functional molecule to a recombinant β helical protein to obtain a conjugate; (b) further incorporating to the conjugate any one signal sequence selected from the group consisting of SEQ ID NO: 14, SEQ ID NO: 15, and SEQ ID NO: 16; (c) contacting the conjugate of step (b) with at least one cell; wherein contacting the conjugate of step (b) transfers the functional molecule to the organelle inside the cell, wherein the organelle is selected from the group consisting of nucleus, endoplasmic reticulum, and mitochondria, and wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm. In an embodiment, the process further comprises after step (c), step (d) detecting the transfer of the conjugate inside the cell.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to an organelle of a cell as described herein, wherein the recombinant β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring the functional molecules to nucleus of the cell as described herein, wherein the signal sequence is as set forth in SEQ ID NO: 14.

In an embodiment of the present disclosure, there is provided a process for transferring the functional molecules to endoplasmic reticulum of the cell as described herein, wherein the signal sequence is as set forth in SEQ ID NO: 15.

In an embodiment of the present disclosure, there is provided a process for transferring the functional molecules to mitochondria of the cell as described herein, wherein the signal sequence is as set forth in SEQ ID NO: 16.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to an organelle of a cell as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to P-cadherin-over expressing breast cancer cells, said process comprising: (a) linking the functional molecule to a recombinant β helical protein to obtain a complex; (b) further incorporating a signal sequence as set forth in SEQ ID NO: 17 to the complex; (c) contacting the complex of step (b) with at least one P-cadherin-over expressing breast cancer cell; wherein contacting the complex of step (b) transfers the functional molecule into the P-cadherin-over expressing breast cancer cell, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm. In an embodiment, the process further comprises after step (c), step (d) detecting the transfer of the complex inside the cell.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to P-cadherin-over expressing breast cancer cells as described herein, wherein the recombinant β helical protein having a sequence is selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, and SEQ ID NO: 12.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to P-cadherin-over expressing breast cancer cells as described herein, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal complex, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process as described herein, wherein the process is used for targeted delivery of the functional molecule into the cell.

In an embodiment of the present disclosure, there is provided a process as described herein, wherein the process is used for labelling of the cell.

In an embodiment of the present disclosure, there is provided a process as described herein, wherein the process is used for targeted delivery of drugs in the cell.

In an embodiment of the present disclosure, there is provided a cell penetrating complex as described herein, wherein the recombinant β helical protein is used for delivering the functional molecule into the cell, and wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal conjugate, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to actin protein present in a cell, said process comprising: (a) linking the functional molecule to a recombinant β helical protein to obtain a conjugate; (b) further incorporating a signal sequence as set forth in SEQ ID NO: 22 to the complex; (c) contacting the conjugate of step (b) with at least one cell; wherein contacting the conjugate of step (b) transfers the functional molecule into the cell, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm. In an embodiment, the process further comprises after step (c), step (d) detecting the transfer of the conjugate inside the cell.

In an embodiment of the present disclosure, there is provided a process for transferring a functional molecule to tubulin protein present in a cell, said process comprising: (a) linking the functional molecule to a recombinant β helical protein to obtain a conjugate; (b) further incorporating a signal sequence as set forth in SEQ ID NO: 23 to the conjugate; (c) contacting the conjugate of step (b) with at least one cell; wherein contacting the conjugate of step (b) transfers the functional molecule into the P-cadherin-over expressing breast cancer cell, wherein the β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm. In an embodiment, the process further comprises after step (c), step (d) detecting the transfer of the conjugate inside the cell.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the recombinant β helical protein is used for cell penetration.

In an embodiment of the present disclosure, there is provided a cell penetrating conjugate as described herein, wherein the recombinant β helical protein is used for cell labelling.

Cell Penetrating Molecule with Nucleic Acid

In an embodiment, the present invention provides a solution to the problem of delivery of nucleic acid fragments, as a functional molecule, that is faced by gene therapy treatments. The present document discloses a conjugate comprising a recombinant β helical protein linked to a nucleic acid molecule which can penetrate the cell membrane. In an embodiment, the recombinant β helical protein linked may be linked to one or more nucleic acid molecules, suitably a single nucleic acid molecule, by a linker element, molecule, portion or moiety.

The conjugate comprising recombinant β helical protein, a linker and a plasmid is shown to successfully penetrate the cell membrane to establish the expression of a gene forming the part of the plasmid. The conjugate avoids the pathway of endocytosis and crosses the cell membrane by directly penetrating the membrane. The conjugate hence overcomes the problems faced by entry through endocytosis and at the same time effectively penetrating the cell membrane.

In an embodiment, the present invention discloses a conjugate capable of penetrating cell membrane. In some embodiments, the conjugate comprises a recombinant β helical protein of length in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm linked to a nucleic acid molecule via a linker. In an embodiment, the recombinant β helical protein can be a pentapeptide repeat protein have a consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅. In another embodiment of the present disclosure, the recombinant β helical protein is selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, and SEQ ID NO: 12.

According to the present disclosure, in an embodiment the recombinant β helical protein is linked to a nucleic acid molecule by a linker element, molecule, portion or moiety. In embodiments, the linker element may be a direct link by covalent or non-covalent bonds. When the linker is a linker molecule it may be selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, and nucleic acid intercalating molecule. In an embodiment, the nucleic acid molecule comprising the part of the conjugate comprises at least one gene of interest. In an embodiment, the nucleic acid molecule is linked to a complex comprising the recombinant β helical protein and the linker to form the conjugate as disclosed in the present invention. In an embodiment, the conjugate is able to enter the cell by penetrating the cell membrane and a gene forming a part of the nucleic acid molecule is able to express inside the cells.

The present invention also discloses a process for transferring a nucleic acid molecule inside the cells using the conjugate of the present invention. In an embodiment, the process disclosed can further be used for gene therapy techniques for facilitating non-viral approaches for delivering the gene of interest in a cell, thereby effectively compensating for a defective gene or protein inside the cell.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is a pentapeptide repeat protein.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the linker is a linker molecule selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule, and combinations thereof.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the linker is a linker molecule selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule, and combinations thereof.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the linker is linked to the recombinant β helical protein by covalent bonds, non-covalent bonds, and combinations thereof.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the linker is a linker molecule selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule and combinations thereof, and wherein the linker is linked to the recombinant β helical protein by covalent bonds, non-covalent bonds, and combinations thereof.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the nucleic acid molecule comprises at least one gene of interest.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the nucleic acid molecule comprises at least one gene of interest.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the linker is a linker molecule selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule and combinations thereof, and wherein the nucleic acid molecule comprises at least one gene of interest.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, l0 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is AlbG having a sequence as set forth in SEQ ID NO: 1.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, l0 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is EfsQNR having a sequence as set forth in SEQ ID NO: 2.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, l0 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 3.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 4.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is an anti-freeze protein having a sequence as set forth in SEQ ID NO: 5.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is QNRB1 having a sequence as set forth in SEQ ID NO: 6.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is UDP N acetylglucosamine acyltransferase having a sequence as set forth in SEQ ID NO: 7.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is NP275 having a sequence as set forth in SEQ ID NO: 8.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is pectate lyase C having a sequence as set forth in SEQ ID NO: 9.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is a pectate lyase having a sequence as set forth in SEQ ID NO: 10.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is carbonic anhydrase having a sequence as set forth in SEQ ID NO: 11.

In an embodiment of the present disclosure, there is provided a conjugate comprising: (a) at least one recombinant β helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm, and wherein the β helical protein is Pectin Lyase A having a sequence as set forth in SEQ ID NO: 12.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell, said process comprising: (i) linking the nucleic acid molecule to a complex comprising: (a) at least one recombinant β helical protein; and (b) at least one linker to obtain a conjugate; and (ii) contacting the conjugate to at least one cell, wherein contacting the conjugate transfers the nucleic acid molecule into the cell, and wherein the recombinant β helical protein length is in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the β helical protein is a pentapeptide repeat protein.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the linker is a linker molecule selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof, and wherein the linker is a linker molecule selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the linker is linked to the recombinant β helical protein by covalent bonds, non-covalent bonds, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the linker is a linker molecule selected from the group consisting of protein, metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule and combinations thereof, and wherein the linker is linked to the recombinant β helical protein by covalent bonds, non-covalent bonds, and combinations thereof.

In an embodiment of the present disclosure, there is provided a process for transferring a nucleic acid molecule into a cell as described herein, wherein the cell is either a prokaryotic cell or a eukaryotic cell.

In an embodiment of the present disclosure, there is provided a conjugate as described herein, wherein the conjugate is used as a transfecting agent.

In an embodiment of the present disclosure, there is provided a conjugate as described herein, wherein the conjugate is used for gene therapy.

EXAMPLES Cell Penetrating Molecule with Functional Molecules

The disclosure will now be illustrated with working examples, which is intended to illustrate the working of disclosure and not intended to take restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice of the disclosed processes and compositions, the exemplary processes, devices and materials are described herein. It is to be understood that this disclosure is not limited to particular methods, and experimental conditions described, as such processes and conditions may vary.

In the following examples, methods and protocols for carrying out plasmid and protein studies have been provided. Also provided are the protocols for obtaining the conjugate, labelling of the protein, and methods of carrying out cell penetration studies using protein-drug conjugate and protein-label conjugate. The results section specifically describes the proof-of-concept of the cell penetration ability of the conjugate as disclosed in the present invention. The in-vitro labelling of different cell lines has been carried out using the conjugate of the present invention as per the method disclosed. The assay with a drug-protein conjugate have also been carried out to study the ability of the conjugate in enhancing the drug uptake by cell penetration.

Material and Methods

The dye Hoechst 33342 was procured from Invitrogen; NHS-coumarin, and ATTO 520-NHS, ATTO 390-NHS and ATTO 647N-NHS were procured from Sigma. The organic solvents and reagents used for UV-visual spectrophotometry and CD spectra were procured from Sigma and Merck. The reagents for studying the expression of plasmids and purification of proteins were procured from Sigma Aldrich and Merck. The reagents required for MTT assay were procured from MP Biomedicals. Ruthenium metal complex was procured from Sigma.

Example 1

Plasmid/Protein studies—The plasmid containing AlbG gene as shown in SEQ ID NO: 19, was obtained by a method as published previously (Vetting et al. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 2011: 67(3): 296-302, the contents of which is incorporated herein by reference and specific details provided below).

The open reading frame of AlbG was amplified by standard PCR techniques using X albilineans (ATCC 29184; Pieretti et al., BMC Genomics, 2009, 10:616, 1-15) chromosomal DNA as a template. The oligonucleotides AlbGF (5′-ATCCCGCTCATATGCCGGCCAAGACCCTTG-3′) and AlbGR (5′-ATCCCGCTCTCGAGTCAATCGGACAGCTCGATATC-3′) containing NdeI and XhoI restriction sites, respectively, were used. The PCR fragment was cloned into pET-28a(+) and recombinant AlbG bearing a thrombin-cleavable N-terminal His6 tag was expressed in E. coli strain BL21 (DE3). For shake-flask growth, 1 liter of Luria broth medium supplemented with kanamycin (35 μg/ml) was inoculated with 10 ml of an overnight culture and incubated at 37° C. The culture was grown to mid-log phase (A₆₀₀ of ˜0.8), cooled to 20° C., induced with 0.5 mM IPTG and further incubated overnight at 20° C. All purification procedures were carried out at 4° C. The cells were collected by centrifugation at 3000 g, re-suspended in buffer A [50 mM Tris-HCl pH 7.8 containing 300 mM NaCl, protease inhibitors, lysozyme (5 μg/ml) and DNase I (0.1 μg/ml)] and stirred for 20 min. The cells were then lysed by sonication and cell debris was removed by centrifugation at 10 000g for 30 min. The supernatant was loaded onto a nickel-nitrilotriacetic acid (Ni-NTA) column pre-equilibrated with buffer A and washed with ten column volumes of the same buffer. The bound proteins were eluted with a linear 0 to 0.3 M imidazole gradient and the peak fractions were pooled and concentrated.

The plasmid containing EfsQNR gene as shown in SEQ ID NO: 20 was obtained by a method as published previously (Hegde et al., Antimicrob. Agents Chemother. 2011 January; 55(1): 110-117, the contents of which is incorporated herein by reference and details provided below).

The open reading frame of EfsQNR was amplified by standard PCR techniques using E. faecalis V583 (ATCC 700802; ENTFA 226185) chromosomal DNA as the template. The oligonucleotides (5′-ATCCCGCTCATATGAAAATAACTTATCCCTTGCCA-3′) and (5′-ATCCCGCTCTCGAGTTAGGTAATCACCAAACCAAGT-3′), containing NdeI and XhoI restriction sites, respectively, were used. The PCR fragment was cloned into pET-28a(+), and the recombinant EfsQNR bearing a thrombin-cleavable N-terminal His6 tag was expressed in E. coli strain BL21(DE3). For shake flask growth, 1 liter of Luria broth medium supplemented with kanamycin (35 μg/ml) was inoculated with 10 ml of an overnight culture and incubated at 37° C. The culture was grown to mid-log phase (A₆₀₀ ˜0.8), cooled to 20° C., induced with 0.5 mM isopropyl-β-d-thiogalactopyranoside (IPTG), and further incubated overnight at 20° C.

The cells were collected by centrifugation at 1,200 g and re-suspended in buffer A (50 mM Tris-HCl [pH 7.8], 300 mM NaCl) containing protease inhibitors, lysozyme (5 μg/ml), and DNase I (0.1 μg/ml), and the mixture was stirred for 20 min. The cells then were lysed by sonication, and cell debris was removed by centrifugation at 10,000 g for 30 min. The supernatant was loaded onto a Ni-NTA column pre-equilibrated with buffer A and washed with 10 column volumes of the same buffer. The bound proteins were eluted with a linear 0 to 0.3 M imidazole gradient with fractions pooled and concentrated.

As a comparative example, a plasmid containing TtCuA gene as shown in SEQ ID NO: 13 was obtained by a method in Biochemistry, 2008, 47, 1309-1318, which is incorporated herein by reference.

Example 2

Toxicity assay—The industry-standard MTT assay (ex-Sigma Aldrich) was performed to analyse the toxicity of β-helical protein-cytotoxic drug conjugates against mammalian cells, for example HeLa cells. The cells were cultured by using standard protocol. One million cells were seeded in confocal plates (1 cm dish), grown for 6-8 h. A mixture of the cytotoxic drug and the EfsQNR protein (mixed at a ratio of 2:1) was added to the cells and incubated at room temperature for 15 minutes to 24 h to 72 h. After the incubation, the cells were washed with PBS and treated with MTT and further incubated for 24 hours. The cells were then washed and analysed for absorbance values at 570 nm. Viable cells with active metabolism convert MTT into a purple coloured formazan product with an absorbance maximum near 570 nm. Dead cells cannot convert MTT into formazan therefore, by analysing the absorbance values at 570 nm percentage of viable cells can be calculated for a given protein or any other molecule.

Example 3

Labelling of proteins with fluorescent dyes—Fluorescent dyes were considered as an example of a functional molecule for investigating the cell membrane penetration ability of the conjugate. Labelling of the recombinant protein with a dye was carried out by performing a series of reaction in dark conditions. The protein to be labelled was collected in PBS buffer (1× and pH 7.3) and the dye was collected at two to three times higher concentration to that of the protein. The protein was added to 0.1M sodium carbonate buffer (pH 8.5) followed by the dye. The dye was added very slowly (30 each time) to the buffer containing the protein kept on ice accompanied by occasional shaking. The resulting solution was wrapped with aluminium foil to keep away any light. The solution was stirred for 1 hour at room temperature and was then purified by gel filtration, i.e. passed through a desalting column or a PD 10 column with 1× PBS buffer. The resulting labelled protein was characterized using UV-visual spectrophotometry to determine dye: protein ratio.

Example 4

Cellular uptake of labelled proteins—The uptake of labelled proteins was checked by treating mammalian cells with different labelled proteins such as AlbG (SEQ ID NO: 1), EfsQNR (SEQ ID NO: 2) and, as a comparative example, TtCuA (SEQ ID NO: 13). TtCuA is a cytochrome oxidase c protein from the organism Thermus thermophilus. It is represented by the amino acid sequence as set forth in SEQ ID NO: 13. The cells were seeded at a concentration of one million in confocal plates (1 cm dish) and allowed to grow for 6-8 hours. Subsequently, the labelled proteins were added to the cells at different concentrations and incubated under standard conditions of 5% CO₂ and 37° C. The cells were then washed twice, after 3 hours and 24 hours with HBSS (Hanks blank salt solution) or PBS and observed under fluorescence microscopy and/or confocal laser scanning microscope.

The uptake of labelled proteins was checked by treating E-Coli and yeast (Kluveromyces) cells with different labelled proteins such as AlbG (SEQ ID NO: 1), EfsQNR (SEQ ID NO: 2). E coli or Kluveromyces cells were inoculated and grown overnight until OD reached 0.6. The cells were diluted to 50 times and 3 micromolar labelled protein (conjugate) was added. The cells were further grown under standard growth condition (37° C. shaking condition) for 24 h. The treated cells were then centrifuged and washed in PBS for 3-4 times. Then the cells were dispersed in 100 microliter PBS and then imaged in fluorescence/confocal microscope.

Example 5

Cellular uptake of drug—HeLa cells were used for determining the enhanced uptake of the drug using the cell penetrating conjugate of the present invention. HeLa cells were seeded at a concentration of 10,000 in a 96-well plate and allowed to grow for 6-8 hours. Ruthenium metal complex and EfsQNR were mixed in different ratios of 1:1, 1:2, and 1:3 to form a conjugate, which was subsequently added to the cells. The conjugate formed of ruthenium to EfsQNR in a ratio of 1:2 yielded an enhanced result. The cell death after 24 hours was monitored by MTT assay as described previously and was correlated to the percentage uptake of ruthenium-EfsQNR conjugate by HeLa cells.

Results of Examples 1 to 5 Characterization of Proteins and Conjugates

Structural specificity—The size of the AlbG protein was determined from the published crystal structure pdb id: 2xt2.pdb. By measuring the end to end atom distance of dimeric structure in Pymol®, the length was determined to be 10.7 nm, and the width (diameter) to be 2.6 nm. The total formal charge was −27. There are alternatively arranged positive and negative charge residues: Presence of an arginine ladder (total of 20 Arg residues), Lysine (14 residues) and aspartic acid (30 Asp residues) and glutamic acid (31 Glu residues). Asparagine (20 Asn residues) ladder along the surface of the protein.

The size of the EfsQNR protein was determined from the published crystal structure pdb id: 2w7z.pdb. By measuring the end to end atom distance of the dimeric structure in Pymol®, the length of the protein was determined to be 10.9 nm, and the width (diameter) to be 2.8 nm. Total formal charge −41. Alternatively arranged positive and negative charge residues: Presence of an arginine ladder (total of 16 Arg residues), Lysine (12 residues) and aspartic acid (25 Asp residues) and glutamic acid (33 Glu residues). Asparagine (33 Asn residues) ladder along the surface of the protein.

For comparison, the size of the TtCuA protein was determined from the published crystal structure pdb id: 2CuA.pdb. By measuring the end to end atom distance of structure in Pymol®, the length was determined to be 3.3 nm, and the width (diameter) to be 1.9 nm. The structure comprises 5 Arginine residues, 4 Lysine residues, 9 Glutamic acid residues and 6 Asparagine residues with a total charge of −3.

FIG. 1 displays the CD spectra of purified AlbG protein (SEQ ID NO: 1) used for the study. Protein was dialyzed in PBS and 1-5 micromolar concentration was used to measure the CD spectroscopy in 200-300 nm region. Further dilution was done with PBS wherever needed. The negative value of CD at 220 nm for this protein indicates arrangement of β sheets (β barrel or β helical structures).

FIG. 2 shows the purified plasmids used for expressing β helical proteins, AlbG and EfsQNR, each showing identical results in triplicate (AlbG-1 to AlbG-3 and EfsQNR-1 to EfsQNR-3).

FIG. 3 shows the purified protein bands of the AlbG and EfsQNR proteins in a polyacrylamide gel. After performing SDS-gel electrophoresis, it was noted that molecular weight of both the proteins in monomer forms were approximately 30 kDa. The approximate molecular weight in dimer forms of AlbG and EfsQNR is around 48 kDa. The proteins, AlbG and EfsQNR were used to form a conjugate with a functional molecule, which was then used to study the cell penetrating efficacy. The proteins were further tested for any cytotoxicity using HeLa cells for determining the course of study (see “Cytotoxicity Studies” below).

FIG. 4 shows the result of a MALDI TOF mass spectrometry analysis of the EfsQNR protein and the AlbG protein. For this experiment, the protein was dialyzed in water and sample was prepared using sinapic acid as matrix with 0.1% TFA and acetonitrile. 1-10 micromolar of protein was used. The results show the EfsQNR protein having a molecular weight of approximately 26.5 kDa, and the AlbG protein having a molecular weight of approximately 23 kDa.

Cytotoxicity Studies

MTT assay as described previously was employed to study toxicity of AlbG and EfsQNR proteins against HeLa cells. For the toxicity assay, samples of Placebo, control, AlbG (30 μM) and EfsQNR (30 μM) were used in triplicates. Table 1 depicts the absorbance values at 570 nm of each sample after treatment with MTT. On observing the values, it can be appreciated that the cells treated with 30 μM of AlbG and 30 μM of EfsQNR display 95% viability as compared to the control cells. This clearly suggests that the tested protein at the tested concentration is not toxic for HeLa cells and hence is a safe concentration to use in further experiments.

Table 1 presented here depicts the absorbance values at 570 nm in MTT assay for evaluating toxicity of the proteins:

TABLE 1 1 2 3 4 5 6 7 8 9 10 11 12 PLACEBO CONTROL EfsQNR AlbG 0.049 0.05 0.046 1.341 1.348 1.413 0.901 1.111 0.971 1.002 1.03 0.932

The placebo for this experiment was 20mM Tris buffer of pH 8.0, whereas, the control considered was only HeLa cells without adding any protein or other substrate.

Labelling Studies

FIG. 4 shows the UV-visual spectrophotometry of the labelled AlbG and EfsQNR conjugates by the procedure as mentioned previously (see “Labelling of proteins with fluorescent dyes” above). The UV-visual spectra was analysed to calculate the labelling ratio of both conjugates. The labelling ratio signifies the number of dyes attached per protein molecule. This is calculated by measuring the ratio between the absorbance values of the dye (at a wavelength depending on the dye used for labelling) and the absorbance of the protein at 280 nm. The dye used for labelling in this experiment was NHS-coumarin. In case of AlbG protein, the dye: protein molecule ratio is observed to be 1.95. In case of EfsQNR the dye: protein molecule ratio is found to be 5.5. The UV-vis spectra confirmed the labelling of both AlbG and EfsQNR proteins with NHS-coumarin dye. The labelled proteins were further used to establish cell penetration in this study.

Cellular Penetration Studies

FIG. 5 shows the fluorescence microscopic images of HeLa cells treated with NHS-C labelled AlbG, EfsQNR, and TtCuA protein (conjugates). The intake of the labelled proteins (conjugates) was compared with the untreated HeLa cells which were considered as a control set for this study. Hoechst Blue is a nuclear labelling dye used along with NHS-C dye which is used for labelling the proteins. The proteins AlbG and EfsQNR are β helical proteins of length in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm representing the recombinant β helical protein of the present invention. However, TtCuA is a protein of length around 4 nm and is composed of β strands forming β barrels, thereby representing a comparative example for the recombinant β helical protein of the present invention. These two different categories of proteins were considered for this study to establish the superior cell penetrating ability of the conjugate of the present invention as compared to different type of β helical protein.

In FIG. 5, panel A represents the control cells which are treated only with nuclear labelling dye (Hoechst Blue) signifying the lack of lighter dye, panel B represents the cells treated with Hoechst Blue dye and with TtCuA-NHSC labelled protein (conjugate), panel C represents the cells treated with Hoechst Blue dye and AlbG-NHSC labelled protein (conjugate) and panel D represents the cells treated with Hoechst Blue dye and EfsQNR-NHSC labelled protein (conjugate). On observing the figure, it can be appreciated that significantly less fluorescence can be seen inside the cells as shown in panel B signifying less presence of TtCuA-NHSC conjugate inside these cells, whereas greater fluorescence can be seen inside the cells represented in panel C and panel D signifying larger presence of AlbG-NHSC conjugate and EfsQNR-NHSC conjugate inside the cells. Therefore, it can be appreciated that TtCuA-NHSC conjugate is not able to effectively penetrate the cell membrane to gain entry inside cells as compared to AlbG-NHSC conjugate and EfsQNR-NHSC conjugate.

On comparing panels C and D, it can be observed that EfsQNR-NHSC conjugate is able to penetrate the membrane more efficiently as compared to the AlbG-NHSC conjugate. Therefore, the cell penetration ability of the three conjugates can be summarised in an increasing order of cell uptake as TtCuA-NHSC<AlbG-NHSC<EfsQNR-NHSC. This further proves the cell penetrating ability of the conjugate comprising a recombinant β helical protein of length and breadth in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm respectively. The conjugates independently comprising AlbG and EfsQNR are able to show enhanced cell permeability as compared to the conjugate comprising TtCuA.

Since the conjugate comprising EfsQNR protein displayed the highest ability to penetrate cell membrane, EfsQNR protein was further studied with different dyes for enhanced labelling of mammalian cells.

FIG. 22 shows in real-time cell entry proceeding via direct interaction of the conjugate with the cell-membrane. To visualise the cells under fluorescence microscopy they were treated with the dye Hoechst 33342 (blue, appearing dark in in FIG. 22) which binds to the nucleus and the dye Alexa 594-WGA (red, appearing lighter in in FIG. 22) which binds to the plasma membrane indicating that the EfsQNR-ATTO-520NHS (green, appearing as light circles in FIG. 22) efficiently penetrates inside the cell by a direct mechanism avoiding any endocytotic mechanism.

Labelling of Mammalian Cells

FIG. 7 depicts the ability of a conjugate comprising EfsQNR conjugated with a dye in labelling of HeLa cells. FIG. 6 depicts the cells labelled with EfsQNR-ATTO-520NHS prepared according to the method of labelling above. The dye Hoechst 33342 (blue, appearing dark in in FIG. 7) binds to the nucleus and the dye Alexa 594-WGA (red, appearing lighter in in FIG. 7) binds to the plasma membrane. The conjugate is formed by linking EfsQNR protein with a green fluorescent dye ATTO-520NHS (appearing as the lightest dye in FIG. 7). It can be clearly observed that the EfsQNR-ATTO-520NHS conjugate penetrates the HeLa cells to lead to efficient labelling (Panel B) of the cells when compared to the control panel A showing HeLa cells which are not treated with the conjugate.

FIG. 8 depicts a similar result for HeLa cells treated with the conjugate formed by linking EfsQNR protein with a blue fluorescent dye ATTO-390NHS (appearing lighter in FIG. 8)

FIG. 9 depicts a similar result for microglial cells labelled with the EfsQNR-ATTO-520NHS which was prepared according to the method of labelling above. Panel A shows significant fluorescence of the dye from inside the cells. Panel B shows microglial cells additionally treated with the dye Hoechst 33342 (blue, appearing dark in in FIG. 9) which binds to the nucleus and the dye Alexa 594-WGA (red, appearing lighter in in FIG. 9) which binds to the plasma membrane indicating that the EfsQNR-ATTO-520NHS has efficiently penetrated inside the cell.

FIG. 10 depicts a similar result for keratinocyte cells labelled with the conjugate EfsQNR-ATTO-520NHS which was prepared according to the method of labelling above. Panel A shows significant fluorescence of the dye from inside the cells. Panel B shows keratinocyte cells additionally treated with the dye Hoechst 33342 (blue, appearing dark in in FIG. 10) which binds to the nucleus indicating that the EfsQNR-ATTO-520NHS has efficiently penetrated inside the cell to be present near the nucleus.

FIG. 11 depicts a similar result for SH-SY5Y cells labelled with the conjugate EfsQNR-ATTO-520NHS which was prepared according to the method of labelling above.

FIG. 12 depicts a similar result for Mouse ES cells labelled with the EfsQNR-ATTO-520NHS which was prepared according to the method of labelling above. FIG. 12 shows Mouse ES cells treated with the dye Hoechst 33342 (blue, appearing dark in in FIG. 12) which binds to the nucleus and the dye Alexa 594-WGA (red, appearing lighter in in FIG. 12) which binds to the plasma membrane indicating that the EfsQNR-ATTO-520NHS has efficiently penetrated inside the cell.

Labelling of Non-Mammalian Cells

FIGS. 13 and 14 depict the ability of a conjugate comprising EfsQNR conjugated with a dye in labelling of E coli and yeast (kluveromyces) cells. FIGS. 13 and 14 depict respectively E coli and yeast (kluveromyces) cells labelled with EfsQNR-ATTO-520NHS prepared according to the method of labelling above.

FACS Sorting of HeLa Cells Treated with the Conjugate

FIG. 15 shows the results of standard FACS sorting of HeLa cells treated with a conjugate labelled with the conjugate EfsQNR-ATTO-647N. Treatment of cells for only 10 minutes (Panel B) leads to significant uptake of the dye compared to the control (Panel A) which continues to increase at 1 h (Panel C) up to the measured 3 h maximum (Panel D).

Drug Uptake Studies

FIG. 16 depicts the cellular uptake of the ruthenium metal complex Ru(CO)3Cl glycinate in HeLa cells. The ruthenium metal complex was conjugated with EfsQNR protein to form a conjugate consisting of ruthenium metal complex-EfsQNR. The HeLa cells were treated with the ruthenium metal complex-EfsQNR conjugate as described above (see “Cellular penetration studies” above) and uptake of the complex was detected by checking the viability of the cells by performing MTT assay as described previously. On observing the graph (FIG. 14), it can be appreciated that upon treatment with only ruthenium metal complex, the cellular uptake is only 0.5%, whereas upon treatment with ruthenium metal complex-EfsQNR protein conjugate the cellular uptake of the complex increases to 24.4%. Therefore, it can be ascertained that the conjugate comprising EfsQNR protein facilitated 50-fold higher cellular uptake as compared to ruthenium metal complex alone. This enhanced uptake can be further exploited by using the conjugate of the present invention to deliver many life-saving drugs to the target thereby reducing the dose of the drug and subsequently decreasing the side-effects.

FIG. 17 shows the results of a viability study of mammalian cells (HeLa and HepG2) cultured with a conjugate comprising EfsQNR protein linked to the chemotherapy drug, Cisplatin® (cisplatinum or cis-diamminedichloroplatinum(II) (CDDP)) labelled ‘CYDD’ in FIG. 17. Mammalian cells (HeLa: Panel A; or HepG2: Panel B) were cultured by using standard protocol. One million cells were seeded in confocal plates (1 cm dish), grown for 8 h. A conjugate comprising Cisplatin® and EfsQNR (prepared in accordance with the method described above in a molar ratio of 2:1) was then added and the culture kept at room temperature for 15 minutes. The cells were kept under standard growth condition for 24 h and 72 h. Then the cells were washed with PBS and MTT solution was added. After the formazan dyes are formed it was dissolved in DMSO and absorbance at 550 nm was measured. It is apparent from the results that in both cell types tested similar cytotoxic efficacy of Cisplatin® is demonstrated with a lower dose when the drug is delivered as a conjugate in accordance with the present invention.

It is noted that in all experiments where tested, similar results were obtained when the EfsQNR protein was replaced with the AlbG protein.

Advantages

Overall, it can be concluded that a conjugate comprising a recombinant β helical protein of specific length and width, and a functional molecule can act as a highly efficient cell membrane penetrating conjugate. The ability of the conjugate to directly penetrate the cell membrane provides advantages as compared to the endocytotic entry mechanism. Working examples of the AlbG-NHSC and EfsQNR-NHSC conjugates are provided in the present disclosure which demonstrate their ability to penetrate the cell membrane. The EfsQNR-dye conjugate is shown to enhance the ability of labelling of a variety of mammalian and non-mammalian cells because of its ability to effectively penetrate the cell membrane. The conjugate comprising EfsQNR and/or AlbG has been shown to increase the cellular uptake of drugs including ruthenium metal complexes and Cisplatin® in HeLa and HepG2 cells. This ability can be further exploited to elevate the uptake of different anti-cancer drugs by cancer cells which can facilitate the treatment by selectively targeting the cancerous cells in an efficient manner and simultaneously with a reduced requirement of the drug. Reduction in the dose of anti-cancer drug can also circumvent the side-effects associated with administration of such drugs.

EXAMPLES Cell Penetrating Molecule with Nucleic Acid

In the following paragraphs, working examples have been provided for delivering a nucleic acid having a gene of interest inside the cell by penetrating the cell membrane. The delivery is made possible because of the use of a conjugate as an embodiment of the present invention which further comprises a nucleic acid molecule. The examples also depict the expression of the gene of interest after penetrating the cell membrane to enter inside the cell.

The example describes transfection of a gene of interest into a cell using an embodiment of the conjugate of the present invention, wherein the gene of interest is mcherry coding for RFP (Red Fluorescent Protein). The plasmid containing mcherry gene is linked to a protein to form a conjugate, wherein the conjugate comprises EfsQNR protein and copper [II] phenanthroline. The conjugate is used to transfect HeLa cells. The successful expression of mcherry gene in HeLa cells is shown as a proof-of-concept to establish the ability of the conjugate to penetrate the cell membrane and transfect the cells.

Material and Methods

Copper phenanthroline complex was commercially procured.

Example 6

Protein Studies—Studies governing the expression of EfsQNR plasmid, conditions of incubation, and purification were followed as published previously (Hegde et al. Antimicrob. Agents and Chemother. 2011: 55(1):110-7 which is incorporated herein by reference) to obtain EfsQNR protein. The SDS-PAGE (polyacrylamide gel electrophoresis) was done using the Bio-Rad kit and the protein bands were visualised using 12% polyacrylamide gel.

Example 7 Preparation of a Conjugate

As is disclosed in the present invention, a conjugate is prepared for transfecting cells, the conjugate comprising EfsQNR (SEQ ID NO: 2), copper [II] phenanthroline, and a plasmid having a gene of interest.

FIG. 18 depicts a vector map of plasmid carrying mcherry gene (SEQ ID NO: 25), used in preparation of the conjugate in the present example. EfsQNR protein (SEQ ID NO: 2) is a β helical protein having a pentapeptide repeat (as depicted in SEQ ID NO: 18) having length in the range of 5 nm-25 nm, suitably, 10 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm. Copper [II] phenanthroline is a nucleic acid intercalating agent used as a linker in the present example.

EfsQNR protein obtained by governing the expression of EfsQNR plasmid was complexed with copper [II] phenanthroline complex to obtain a complex comprising EfsQNR and copper [II] phenanthroline. The obtained complex was further reacted with plasmid having mcherry gene to obtain a conjugate in accordance with an embodiment of the present invention. The obtained conjugate was used to transfect HeLa cells.

FIG. 19 depicts two schemes for preparing the conjugate that can be used for transfection. Scheme 1 suggests the use of copper [II] phenanthroline as a linker which forms a complex with a protein. The obtained complex is further reacted with a plasmid having a gene of interest to obtain the conjugate to be used for transfection.

Scheme 2 suggests the use of a DNA binding protein as a linker which forms a complex with a protein. The obtained complex is further reacted with a plasmid having a gene of interest to obtain the conjugate to be used for transfection.

In the present example, copper [II] phenanthroline is used as a linker to form a complex and a recombinant β helical protein-EfsQNR (SEQ ID NO: 2) is used along with a plasmid containing mcherry gene. The following protocol was used for preparing the complex and the conjugate:

The protein EfsQNR was mixed with copper [II] phenanthroline in a 1:2 molar ratio and incubated for 30 minutes as room temperature to obtain the complex. Plasmid containing mcherry gene was mixed with the complex obtained in previous step and incubated for 30 minutes at 4 ° C. to obtain the conjugate. The conjugate so obtained was used to transfect HeLa cells.

Example 8 Transfection of HeLa Cells Using the Conjugate

FIG. 20 depicts a scheme for transfection experiment using the conjugate obtained in Example 9. In the present example following conditions were used for performing the transfection experiment.

The conjugate comprising the mcherry plasmid as obtained in Example 8 was added to HeLa cells (8 hours after seeding). The cells were allowed to grow by incubating at 37° C. and 5% CO₂ conditions for 48 hours. After the incubation, the cells were observed under confocal microscopy.

FIG. 21 depicts confocal microscopy images of HeLa cells after the transfection experiment. The expression of RFP can be observed as lighter (red) dots inside the HeLa cells thereby, proving the cell penetration and transfecting ability of the conjugate disclosed in the present document.

Although the example as presented herein shows the use of protein EfsQNR (SEQ ID NO: 2) in the preparation of a conjugate for transfection, the proteins having amino acid sequence as depicted in SEQ ID NO: 1 and SEQ ID NO: 3 to SEQ ID NO: 12 can also be used effectively to form the conjugate. Also, recombinant β helical proteins having a penta-peptide repeat sequence as depicted in SEQ ID NO: 18 and having a length in the range of 5 nm-25 nm, suitably, l0 nm-15 nm and width is in the range of 1 nm-5 nm, suitably 1 nm-3 nm can be used for preparing the conjugate as described in the present disclosure. Similarly, the present example depicts the use of copper [II] phenanthroline as a linker but other molecules like DNA binding protein, metal conjugate, drug metal conjugate, and other nucleic acid intercalating molecule can also be used in the formation of a conjugate to be used effectively as a transfecting agent. One class of a DNA binding protein namely, zinc finger protein having a molecular weight of less than 12 kDa can also be used to form the conjugate. One such zinc finger protein that can be used as a linker has been depicted in SEQ ID NO: 24. In the present disclosure, a plasmid (FIG. 18) carrying mcherry gene has been used for preparing the conjugate for transfection and the expression of mcherry gene has been shown as a proof-of-concept. It is contemplated that essentially any gene of interest for transfection purpose can be complexed with the complex as disclosed herein to form the conjugate for use in gene therapy.

Advantages

The present disclosure provides with a conjugate comprising a gene of interest which possess the ability of penetrating cell membrane and expressing the gene of interest. Hence, the conjugate can be used for transfection and has immense potential to be used in gene therapy. As is known that delivery of the gene to the cells is a major challenge in the field of gene therapy, the disclosed conjugate opens new avenue in this field. The disclosed conjugate is simple to prepare and can be complexed with wide variety of genes to be used for gene therapy.

Although particular embodiments of the invention have been disclosed herein in detail, this has been done by way of example and for the purposes of illustration only. The aforementioned embodiments are not intended to be limiting with respect to the scope of the invention. It is contemplated by the inventors that various substitutions, alterations, and modifications may be made to the invention without departing from the spirit and scope of the invention.

TABLE 2 List of sequences SEQ ID Sequences SEQ ID NO: 1-Protein MPAKTLESKDYCGESFVSEDRSGQSLESIRFEDCTFRQCNFTEAEL NRCKFRECEFVDCNLSLISIPQTSFMEVRFVDCKMLGVNWTSAQW PSVKMEGALSFERCILNDSLFYGLYLAGVKMVECRIHDANFTEAD CEDADFTQSDLKGSTFHNTKLTGASFIDAVNYHIDIFHNDIKRARF SLPEAASLLNSLDIELSD SEQ ID NO: 2-Protein GSHMKITYPLPPNLPEQLPLLTNCQLEDEAILENHLYQQIDLPNQE VRNLVFRDAVFDHLSLANGQFASFDCSNVRFEACDFSNVEWLSG SFHRVTFLRCNLTGTNFADSYLKDCLFEDCKADYASFRFANFNLV HFNQTRLVESEFFEVTWKKLLLEACDLTESNWLNTSLKGLDFSQN TFERLTFSPNYLSGLKVTPEQAIYLASALGLVIT SEQ ID NO: 3-Protein QCTGGADCTSCTGACTGCGNCPNAVTCTNSQHCVKANTCTGSTD CNTAQTCTNSKDCFEANTCTDSTNCYKATACTNSSGCPGH SEQ ID NO: 4-Protein GYSCRAVGVDGRAVTDIQGTCHAKATGAGAMASGTSEPGSTSTA TATGRGATARSTSTGRGTATTTATGTASATSNAIGQGTATTTATG SAGGRATGSATTSSSASQPTQTQTITGPGFQTAKSFARNTATTTVT ASHHHHHH SEQ ID NO: 5-Protein DGSCTNTNSQLSANSKCEKSTLTNCYVDKSEVYGTTCTGSRFDGV TITTSTSTGSRISGPGCKISTCIITGGVPAPSAACKISGCTFSAN SEQ ID NO: 6-Protein GSHMALALVGEKIDRNRFTGEKIENSTFFNCDFSGADLSGTEFIGC QFYDRESQKGCNFSRAMLKDAIFKSCDLSMADFRNSSALGIEIRH CRAQGADFRGASFMNMITTRTWFCSAYITNTNLSYANFSKVVLE KCELWENRWIGAQVLGATFSGSDLSGGEFSTFDWRAANFTHCDL TNSELGDLDIRGVDLQGVKLDNYQASLLMERLGIAVIG SEQ ID NO: 7-Protein MIDKSAFVHPTAIVEEGASIGANAHIGPFCIVGPHVEIGEGTVLKSH VVVNGHTKIGRDNEIYQFASIGEVNQDLKYAGEPTRVEIGDRNRIR ESVTIHRGTVQGGGLTKVGSDNLLMINAHIAHDCTVGNRCILANN ATLAGHVSVDDFAIIGGMTAVHQFCIIGAHVMVGGCSGVAQDVPP YVIAQGNHATPFGVNIEGLKRRGFSREAITAIRNAYKLIYRSGKTL DEVKPEIAELAETYPEVKAFTDFFARSTRGLIR SEQ ID NO: 8-Protein MGSSHHHHHHSSGLVPRGSHMDVEKLRQLYAAGERDFSIVDLRG AVLENINLSGAILHGAMLDEANLQQANLSRADLSGATLNGADLR GANLSKADLSDAILDNAILEGAILDEAVLNQANLKAANLEQAILS HANIREADLSEANLEAADLSGADLAIADLHQANLHQAALERANLT GANLEDANLEGTILEGGNNNLAT SEQ ID NO: 9-Protein ATDTGGYAATAGGNVTGAVSKTATSMQDIVNIIDAARLDANGKK VKGGAYPLVITYTGNEDSLINAAAANICGQWSKDPRGVEIKEFTK GITIIGANGSSANFGIWIKKSSDVVVQNMRIGYLPGGAKDGDMIRV DDSPNVWVDHNELFAANHECDGTPDNDTTFESAVDIKGASNTVT VSYNYIHGVKKVGLDGSSSSDTGRNITYHHNYYNDVNARLPLQR GGLVHAYNNLYTNITGSGLNVRQNGQALIENNWFEKAINPVTSR YDGKNFGTWVLKGNNITKPADFSTYSITWTADTKPYVNADSWTS TGTFPTVAYNYSPVSAQCVKDKLPGYAGVGKNLATLTSTACK SEQ ID NO: 10-Protein VGTNTGGVLVITDTIIVKSGQTYDGKGIKIIAQGMGDGSQSENQKP IFKLEKGANLKNVIIGAPGCDGIHCYGDNVVENVVWEDVGEDAL TVKSEGVVEVIGGSAKEAADKVFQLNAPCTFKVKNFTATNIGKLV RQNGNTTFKVVIYLEDVTLNNVKSCVAKSDSPVSELWYHNLNVN NCKTLFEFPSQSQIHQY SEQ ID NO: 11-Protein QEITVDEFSNIRENPVTPWNPEPSAPVIDPTAYIDPQASVIGEVTIG ANVMVSPMASIRSDEGMPIFVGDRSNVQDGVVLHALETINEEGEPIE DNIVEVDGKEYAVYIGNNVSLAHQSQVHGPAAVGDDTFIGMQAF VFKSKVGNNCVLEPRSAAIGVTIPDGRYIPAGMVVTSQAEADKLP EVTDDYAYSHTNEAVVYVNVHLAEGYKETS SEQ ID NO: 12-Protein VGVSGSAEGFAKGVTGGGSATPVYPDTIDELVSYLGDDEARVIVL TKTFDFTDSEGTTTGTGCAPWGTASACQVAIDQDDWCENYEPDA PSVSVEYYNAGTLGITVTSNKSLIGEGSSGAIKGKGLRIVSGAENII IQNIAVTDINPKYVWGGDAITLDDCDLVWIDHVTTARIGRQHYVLGT SADNRVSLTNNYIDGVSDYSATCDGYHYWAIYLDGDADLVTMKGNY IYHTSGRSPKVQDNTLLHAVNNYWYDISGHAFEIGEGGYVLAEGNVF QNVDTVLETYEGEAFTVPSSTAGEVCSTYLGRDCVINGFGSSGTFS EDSTSFLSDFEGKNIASASAYTSVASRVVANAGQGNL SEQ ID NO: 13-Protein AYTLATHTAGVIPAGKLERVDPTTVRQEGPWADPAQAVVQTGPN QYTVYVLAFAFGYQPNPIEVPQGAEIVFKITSPDVIHGFHVEGTNIN VEVLPGEVSTVRYTFKRPGEYRIICNQYCGLGHQNMFGTIVVKE SEQ ID NO: 14-Peptide PAAKRVKCD SEQ ID NO: 15-Peptide YPYDVPDYAKDEL SEQ ID NO: 16-Peptide MLSLRQSIRFFKPATRTLCSSRYLL SEQ ID NO: 17-Peptide LSTAADMQGVVTDGMASGLDKDYLKPDD SEQ ID NO: 18-consensus (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅ sequence SEQ ID NO: 19-DNA ATGCCGGCGAAAACCCTGGAAAGCAAAGATTATTGCGGCGAA AGCTTTGTGAGCGAAGATCGCAGCGGCCAGAGCCTGGAAAGC ATTCGCTTTGAAGATTGCACCTTTCGCCAGTGCAACTTTACCGA AGCGGAACTGAACCGCTGCAAATTTCGCGAATGCGAATTTGTG GATTGCAACCTGAGCCTGATTAGCATTCCGCAGACCAGCTTTA TGGAAGTGCGCTTTGTGGATTGCAAAATGCTGGGCGTGAACTG GACCAGCGCGCAGGCGGGCGCGCTGAGCTTTGAACGCTGCATT CTGAACGATAGCCTGTTTTATGGCCTGTATCTGGCGGGCGTGA AAATGGTGGAATGCCGCATTCATGATGCGAACTTTACCGAAGC GGATTGCGAAGATGCGGATTTTACCCAGAGCGATCTGAAAGGC AGCACCTTTCATAACACCAAACTGACCGGCGCGAGCTTTATTG ATGCGGTGAACTATCATATTGATATTTTTCATAACGATATTAAA CGCGCGCGCTTTAGCCTGCCGGAAGCGGCGAGCCTGCTGAACA GCCTGGATATTGAACTGAGCGAT SEQ ID NO: 20-DNA GGCAGCCATATGAAAATTACCTATCCGCTGCCGCCGAACCTGC CGGAACAGCTGCCGCTGCTGACCAACTGCCAGCTGGAAGATGA AGCGATTCTGGAAAACCATCTGTATCAGCAGATTGATCTGCCG AACCAGGAAGTGCGCAACCTGGTGTTTCGCGATGCGGTGTTTG ATCATCTGAGCCTGGCGAACGGCCAGTTTGCGAGCTTTGATTG CAGCAACGTGCGCTTTGAAGCGTGCGATTTTAGCAACGTGGAA TGGCTGAGCGGCAGCTTTCATCGCGTGACCTTTCTGCGCTGCAA CCTGACCGGCACCAACTTTGCGGATAGCTATCTGAAAGATTGC CTGTTTGAAGATTGCAAAGCGGATTATGCGAGCTTTCGCTTTGC GAACTTTAACCTGGTGCATTTTAACCAGACCCGCCTGGTGGAA AGCGAATTTTTTGAAGTGACCTGGAAAAAACTGCTGCTGGAAG CGTGCGATCTGACCGAAAGCAACTGGCTGAACACCAGCCTGAA AGGCCTGGATTTTAGCCAGAACACCTTTGAACGCCTGACCTTT AGCCCGAACTATCTGAGCGGCCTGAAAGTGACCCCGGAACAG GCGATTTATCTGGCGAGCGCGCTGGGCCTGGTGATTACC SEQ ID NO: 21-DNA GCGTATACCCTGGCGACCCATACCGCGGGCGTGATTCCGGCGG GCAAACTGGAACGCGTGGATCCGACCACCGTGCGCCAGGAAG GCCCGTGGGCGGATCCGGCGCAGGCGGTGGTGCAGACCGGCC CGAACCAGTATACCGTGTATGTGCTGGCGTTTGCGTTTGGCTAT CAGCCGAACCCGATTGAAGTGCCGCAGGGCGCGGAAATTGTGT TTAAAATTACCAGCCCGGATGTGATTCATGGCTTTCATGTGGA AGGCACCAACATTAACGTGGAAGTGCTGCCGGGCGAAGTGAG CACCGTGCGCTATACCTTTAAACGCCCGGGCGAATATCGCATT ATTTGCAACCAGTATTGCGGCCTGGGCCATCAGAACATGTTTG GCACCATTGTGGTGAAAGAA SEQ ID NO: 22-peptide GDVQKKRWLFETKPLD SEQ ID NO: 23-peptide VQSKCGSKDNIKHVPGGG SEQ ID NO: 24-peptide MERPYACPVESCDRRFSDSSNLTRHIRIHTGQKPFQCRICMRNFSR SDHLTTHIRTHTGEKPFACDICGRKFARSDERKRHTKIHLRQKD SEQ ID NO: 25-peptide GTGAGCAAGGGCGAGGAGGATAACATGGCCATCATCAAGGAG TTCATGCGCTTCAAGGTGCACATGGAGGGCTCCGTGAACGGCC ACGAGTTCGAGATCGAGGGCGAGGGCGAGGGCCGCCCCTACG AGGGCACCCAGACCGCCAAGCTGAAGGTGACCAAGGGTGGCC CCCTGCCCTTCGCCTGGGACATCCTGTCCCCTCAGTTCATGTAC GGCTCCAAGGCCTACGTGAAGCACCCCGCCGACATCCCCGACT ACTTGAAGCTGTCCTTCCCCGAGGGCTTCAAGTGGGAGCGCGT GATGAACTTCGAGGACGGCGGCGTGGTGACCGTGACCCAGGA CTCCTCCCTCCAGGACGGCGAGTTCATCTACAAGGTGAAGCTG CGCGGCACCAACTTCCCCTCCGACGGCCCCGTAATGCAGAAGA AGACCATGGGCTGGGAGGCCTCCTCCGAGCGGATGTACCCCGA GGACGGCGCCCTGAAGGGCGAGATCAAGCAGAGGCTGAAGCT GAAGGACGGCGGCCACTACGACGCTGAGGTCAAGACCACCTA CAAGGCCAAGAAGCCCGTGCAGCTGCCCGGCGCCTACAACGTC AACATCAAGTTGGACATCACCTCCCACAACGAGGACTACACCA TCGTGGAACAGTACGAACGCGCCGAGGGCCGCCACTCCACCGG CGGCATGGACGAGCTGTACAAGTAGTAATCTAGAGGGCCCTAT TCTATAGTGTCACC SEQ ID NO: 26-DNA ATCCCGCTCATATGCCGGCCAAGACCCTTG SEQ ID NO: 27-DNA ATCCCGCTCTCGAGTCAATCGGACAGCTCGATATC SEQ ID NO: 28-DNA ATCCCGCTCATATGAAAATAACTTATCCCTTGCCA SEQ ID NO: 29-DNA ATCCCGCTCTCGAGTTAGGTAATCACCAAACCAAGT 

1. A cell penetrating conjugate comprising a recombinant β helical protein linked to a functional molecule, wherein the β helical protein length is in the range of from 5 nm to 25 nm, and width is in the range of from 1 nm to 5 nm; wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅. 2.-9. (canceled)
 10. The cell penetrating conjugate as claimed in claim 1, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof.
 11. The cell penetrating conjugate as claimed in claim 1, wherein the recombinant β helical protein is linked to the functional molecule via a linker molecule selected from the group consisting of: polyethyleneglycol (PEG); peptide; metal conjugate, drug-metal conjugate, DNA binding domain, nucleic acid intercalating molecule and combinations thereof.
 12. The cell penetrating conjugate as claimed in claim 11, wherein when the linker molecule is a peptide, the peptide comprises amino acids selected from the group consisting of: aliphatic amino acids; aromatic amino acids; and combinations thereof.
 13. The cell penetrating conjugate as claimed in claim 1, wherein the linker and the recombinant β helical protein are linked by one or more of the group consisting of: covalent bonds, non-covalent bonds, and combinations thereof.
 14. The cell penetrating conjugate as claimed in claim 1, wherein the recombinant β helical protein is linked to a functional molecule by a linkage selected from the group consisting of an ester linkage and an amide linkage.
 15. The cell penetrating conjugate as claimed in claim 1, wherein the functional molecule is selected from the group consisting of dyes, drugs, metal, drug-metal conjugate, proteins, enzymes, antibodies, nucleic acids, polysaccharides, nuclear localizing signals, nanoparticles, and combinations thereof.
 16. The cell penetrating conjugate as claimed in claim 1, wherein the conjugate further comprises a signal sequence wherein the signal sequence directs the conjugate to a particular cell or part of a cell.
 17. The cell penetrating conjugate as claimed in claim 16, wherein the signal sequence is selected from the group consisting of SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, and SEQ ID NO:
 17. 18. The cell penetrating conjugate as claimed in claim 1, wherein the conjugate further comprises a phosphatidyl choline molecule.
 19. The cell penetrating conjugate as claimed in claim 16, wherein the conjugate is transfers the functional molecule to a location selected from the group consisting of: cell organelles; nucleus; endoplasmic reticulum; mitochondria; cell membrane; and P-cadherin overexpressing breast cancer cells.
 20. The cell penetrating conjugate as claimed in claim 19, wherein the cell organelles are selected from the group comprising actin filaments, golgi bodies, cell membrane, microtubulins. 21.-22. (canceled)
 23. A process for transferring a functional molecule into a cell, said process comprising: a) linking the functional molecule to a recombinant β helical protein to obtain a conjugate; b) contacting the conjugate with at least one cell; wherein contacting the conjugate of step (b) transfers the functional molecule into the cell; and wherein the β helical protein length is in the range of from 5 nm to 25 nm and width is in the range of from 1 nm to 5 nm.
 24. The process as claimed in claim 23, wherein the process comprises after step (b): c) detecting the transfer of the conjugate inside the cell.
 25. The process as claimed in claim 23, wherein the conjugate is the cell penetrating conjugate of claim
 1. 26.-35. (canceled)
 36. The process as claimed in claim 23, wherein the cell is selected from the group consisting of eukaryotic cells, prokaryotic cells, and combinations thereof. 37.-40. (canceled)
 41. A conjugate, wherein the conjugate comprises: (i) (a) at least one recombinant ₃ helical protein; (b) at least one linker; and (c) at least one nucleic acid molecule, wherein the at least one recombinant ₃ helical protein length is in the range of from 5 nm to 25 nm, and width is in the range of from 1 nm to 5 nm; and wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅; (ii) (a) at least one recombinant β helical protein; (b) at least one linker; and (c) a functional molecule, wherein the functional molecule is at least one protein, wherein the at least one recombinant β helical protein length is in the range of from 5 nm to 25 nm, and width is in the range of from 1 nm to 5 nm and; wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅; or (iii) (a) at least one recombinant 13 helical protein; (b) at least one linker; and (c) a functional molecule, wherein the functional molecule is at least one quantum dot, wherein the at least one recombinant β helical protein length is in the range of from 5 nm to 25 nm, and width is in the range of from 1 nm to 5 nm and; wherein the β helical protein comprises tandemly repeated pentapeptide with consensus sequence (STAV)₁(DN)₂(LF)₃(STR)₄(G)₅. 42.-49. (canceled)
 50. The conjugate as claimed in claim 41, wherein the β helical protein is represented by a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, and combinations thereof. 51.-54. (canceled)
 55. The conjugate as claimed in claim 41, wherein the nucleic acid molecule comprises at least one gene of interest. 56.-73. (canceled) 